The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
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The Supplemental Poverty Measure: Its Core
Concepts, Development, and Use
Updated July 19, 2022
Congressional Research Service
https://crsreports.congress.gov
R45031
The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Summary
The Supplemental Poverty Measure (SPM) is a measure of economic deprivation—having
insufficient financial resources to achieve a specified standard of living. The SPM addresses some
of the limitations of the official poverty measure, without supplanting it outright.
Both the SPM and the official measure determine the poverty status of people and families by
comparing their financial resources against poverty thresholds that are valued in dollars. For both
measures, poverty thresholds vary by family size and composition, and families whose resources
are lower than the thresholds are considered to be poor.
The measures differ in their definitions of
need, as it is used in the thresholds (the dollar amounts used to determine poverty
status),
financial resources that are considered relevant for comparing against the
measure of need as specified in the thresholds, and
family, for the purpose of assigning thresholds and counting resources.
Need
The official poverty measure thresholds are based on the costs of austere food budgets developed
using data from the 1950s and 1960s, with the threshold dollar amounts updated annually for
inflation. The official poverty thresholds vary by family size and composition. In contrast, the
SPM thresholds for any given year are based on a below-median level of consumer expenditures
for food, clothing, shelter, and utilities developed using data for five recent years. The SPM
thresholds vary to reflect that
housing costs differ between homeowners with mortgages, homeowners without
mortgages, and renters;
housing costs differ geographically; and
costs differ by family size and composition.
Financial Resources
Financial resources to meet needs, whether in the SPM or the official measure, are based on the
sum of income of all family members. While the official measure uses money income before
taxes, the SPM makes additional adjustments and considers a wider range of resources. The SPM
includes the value of certain in-kind benefits (such as food and housing subsidies), uses income
after estimated federal and state taxes, and subtracts some expenses from income. These expenses
include medical out-of-pocket costs, such as health insurance premiums, physician co-pays, and
over-the-counter medications; child support paid outside of the household; and work expenses,
such as child care and the cost of commuting, tools, uniforms, or licensing fees related to a
person’s employment. Work expenses, including child care, are capped at the amount of earnings
from work of the lowest-earning family member. These expenses are subtracted from family
income because they cannot be used to obtain the needs defined in the SPM thresholds. Unlike
the official poverty measure, the range of financial resources included in the SPM is defined to be
consistent with the types of needs used to compute the SPM poverty thresholds.
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Family
Like the official measure, the SPM family unit definition includes people related by birth,
marriage, or adoption living in the same housing unit. However, the SPM additionally includes
cohabiting couples and their children, and foster children below age 22.
How Does Poverty Look through the Lens of the SPM?
The demographic profile of the poverty population is different under the SPM than under the
official measure. Children have a comparatively lower poverty rate (percentage in poverty) under
the SPM, and the aged (65 and older) have a comparatively higher poverty rate. Among workingage persons (18 to 64), the SPM poverty rate was lower than the official rate in 2020, although in
previous years the reverse was true. These differences can be explained by the SPM’s resource
definition. The SPM includes tax credits and in-kind benefits that help families with children (in
effect, boosting the measure of family income). Stimulus payments sent to households in 2020
help to explain the comparatively lower poverty rate among working-age persons in the SPM that
year compared to the official measure. Typically, however, because the SPM subtracts workrelated expenses, the income for working-age adults appeared lower under the SPM than the
official measure (before 2020), and as a result their SPM poverty rates had been comparatively
higher. The SPM also subtracts medical out-of-pocket expenses, which disproportionately affects
the aged (lowering their measure of income).
Uses and Limits
The SPM can give policymakers the tools to understand how taxes and government programs,
including the noncash programs, affect the poor. It also illustrates how medical expenses and
work-related expenses such as child care can affect a family’s economic well-being. However, the
SPM poverty estimates are derived from household survey data, and hence are affected by issues
such as underreporting of income from government benefit programs, limitations on how tax
liabilities and tax benefits can be estimated based on survey data, and differences in how noncash
benefits and lump-sum tax refunds are valued by program recipients versus how they are valued
for the purposes of poverty measurement. Additionally, the SPM does not directly value health
insurance provided publicly or privately. Further, poverty has historically been measured in the
United States as an absolute measure, based on how many people fall below a set standard of
living. Questions have been raised about whether the SPM continues to measure poverty in that
way, or represents a relative measure of poverty, based on how portions of the population rank in
terms of well-being relative to each other.
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Contents
Introduction ..................................................................................................................................... 1
The Official Measure of Poverty ............................................................................................... 1
What is the SPM? ...................................................................................................................... 2
Broadly Comparing the Official Poverty Measure to the SPM ................................................. 2
The Supplemental Poverty Measure: Research to Address Limitations of the Official
Poverty Measure........................................................................................................................... 4
Criticisms of the Official Poverty Measure ............................................................................... 4
Motivation for a New Poverty Measure .................................................................................... 5
Moving Toward the SPM: Decades of Research....................................................................... 6
Multiple Series of Alternative Poverty Measures ............................................................... 6
Developing the SPM: Consolidating the Research, and Public Comment ......................... 7
How Is the SPM Currently Computed? ........................................................................................... 7
Definition of Need in SPM Poverty Thresholds ....................................................................... 8
Goods and Their Costs ........................................................................................................ 8
Adjustment of the Thresholds by Homeownership or Rental Status ................................ 10
Adjustment of the Thresholds by Geographic Variations in Housing Costs ..................... 10
Adjustment of the Thresholds by Family Size ................................................................... 11
Adjustment of the Thresholds for Changes over Time ...................................................... 11
Definition of Resources in SPM Poverty Thresholds ............................................................. 12
Money Income and Other Resources ................................................................................ 13
Expenses Subtracted from Income.................................................................................... 15
Family Units in the SPM ......................................................................................................... 17
Use of the SPM.............................................................................................................................. 18
Insights Obtainable from the SPM .......................................................................................... 18
Effects of Transfer Programs, Taxes, Tax Credits, and Expenses ..................................... 18
Comparison of Impacts among Resource Components .................................................... 21
Differences in the Demographic Profile of the Poor ......................................................... 21
Geographic Differences .................................................................................................... 23
Limitations of the SPM and Outstanding Issues ..................................................................... 23
Data Considerations .......................................................................................................... 23
Cash Valuation of Noncash Benefits: Not Fully Interchangeable ..................................... 24
Out-of-Pocket Medical Costs Are Measured, But Not the Full Benefit of Medical
Subsidies ........................................................................................................................ 24
Lump Sum Nature of Tax Credits ..................................................................................... 25
Nature of the SPM: a Relative or an Absolute Measure?.................................................. 25
Figures
Figure 1. The Effects of Each Transfer, Tax, or Expense on the Number of People
Identified as Below Poverty Using the SPM: 2020 and 2019 .................................................... 20
Figure 2. Median SPM Threshold As a Percentage of Median SPM Resources ........................... 28
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Tables
Table 1. Differences between the Official and Supplemental Poverty Measures ............................ 3
Table A-1. Supplemental Poverty Measure (SPM) Thresholds in 2020 for a Two-Child,
Two-Adult Family in Selected Metropolitan and Nonmetropolitan Areas................................. 30
Table A-2. Supplemental Poverty Measure (SPM) Thresholds by Housing Status, Number
of Adults, and Number of Children under 18 Years, Without Geographic Adjustment:
2020 ............................................................................................................................................ 32
Table A-3. Official Poverty Thresholds for 2020 by Family Size and Number of Related
Children Under 18 Years ............................................................................................................ 35
Appendixes
Appendix. Poverty Thresholds under the SPM and the Official Poverty Measure ....................... 30
Contacts
Author Information........................................................................................................................ 36
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Introduction
As its name might suggest, the Supplemental Poverty Measure (SPM) was developed to
supplement, but not replace, the official poverty measure by addressing some of its
methodological limitations. The official measure provides a consistent historical view of poverty
in the United States, but the SPM may be better suited to helping congressional policymakers and
other experts understand how taxes and government programs affect the poor. Also, it may better
illustrate how certain medical expenses and work-related expenses such as child care can affect a
family’s economic well-being.
This report describes the SPM, how it was developed, how it differs from the official poverty
measure, and the insights it can offer. This report will not discuss potential consequences of
changes to anti-poverty programs, nor will it provide an analysis of poverty trends.1
The Official Measure of Poverty
The official measure of poverty was developed in the 1960s by Mollie Orshansky, an analyst at
the Social Security Administration. It was based on food costs in that decade as well as the share
of a family’s total budget that was devoted to food according to family budgets in the mid-1950s.
The food cost it used was based on a 1962 edition of the U.S. Department of Agriculture’s
(USDA’s) Economy Food Plan.2 A 1955 survey of family consumption determined that about
one-third of a family’s spending was on food. Thus, the poverty thresholds were developed as
three times the cost of the Economy Food Plan, with some adjustments for two-person families
and single individuals to account for their higher fixed costs. In the current official measure of
poverty, the thresholds developed in the 1960s have been adjusted only for price inflation, as
measured by the Consumer Price Index for All Urban Consumers (CPI-U).3
Under the official poverty measure, an individual is counted as poor if his or her family’s pre-tax
money income falls below the poverty threshold. Pre-tax money income excludes the value of
government noncash benefits provided either privately or publicly, such as health insurance,
Supplemental Nutrition Assistance Program (SNAP) benefits, or housing assistance. It also does
not consider taxes paid to federal, state, or local governments, or tax benefits (such as the Earned
Income Tax Credit, EITC) that might be received by families. The official poverty measure is
computed for the non-institutionalized population.
1 For a historical perspective on poverty, an overview of poverty by demographic group, and summary explanations of
the official measure and the SPM, see CRS Report R47030, Poverty in the United States in 2020, by Joseph Dalaker.
For a more thorough introduction to the methods of poverty measurement, see CRS Report R44780, An Introduction to
Poverty Measurement, by Joseph Dalaker.
2 The USDA now uses the Thrifty Food Plan, which underwent a reevaluation and revision in 2021 that resulted in a
21% increase in the plan’s dollar amounts; for details, see https://www.fns.usda.gov/resource/thrifty-food-plan-2021.
However, the official poverty thresholds, while updated annually for inflation, are still based on the 1962 food plans
described in Eloise Cofer, Evelyn Grossman, and Faith Clark, Family Food Plans and Food Costs: For Nutritionists
and Other Leaders Who Develop and Use Food Plans, Home Economics Research Report No. 20, U.S. Department of
Agriculture, Agriculture Research Service, November 1962. A copy of the 1962 report is available at
https://aspe.hhs.gov/sites/default/files/migrated_legacy_files//55156/familyfoodplan.pdf
3 The official poverty measure, as well as its method of inflation adjustment, was established by the Office of
Management and Budget (OMB) in Statistical Policy Directive 14, originally issued in 1969 (as the Bureau of the
Budget’s Circular A-46) and reissued in 1978. The Census Bureau follows this directive when publishing official
poverty statistics.
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What is the SPM?
The SPM was designed to address limitations of the official poverty measure.4 Like the official
poverty measure, it is a measure of economic deprivation. It defines poverty status for families
and individuals by comparing resources against a measure of need.5 Measures of need are used to
establish poverty thresholds that are valued in dollars.
The SPM poverty thresholds measure a standard of living based on expenditures for food,
clothing, shelter, and utilities (FCSU), and “a little more” for other expenses. The resources
measured against those thresholds represent disposable income (after taxes and certain other
expenses), including the value of certain noncash benefits, that are available to families to meet
those needs.
The SPM is considered a research measure, because it is designed to be updated as techniques to
quantify poverty and data sources improve over time, and because it was not intended to replace
either official poverty statistics or eligibility criteria for anti-poverty assistance programs.
Broadly Comparing the Official Poverty Measure to the SPM
Both the SPM and the official measure determine the poverty status of people and families by
comparing their financial resources against poverty thresholds. For both measures, poverty
thresholds vary by family size and composition, and families whose resources are lower than the
thresholds are considered to be poor. The differences between the SPM and the official measure
reflect changes in household composition in the more than 50 years since the official measure
was developed. The differences also partly spring from attempts to more accurately assess the
needs and resources of families. Some of the innovations surrounding the calculation of needs
and resources embodied in the SPM are based on data that were not yet available when the
official measure was developed.
The measures differ in their definitions of the following:
Need, as it is used in the thresholds (the dollar amounts used to determine poverty
status). Unlike the official measure, the SPM’s measure of need is geographically
adjusted based on housing costs by metropolitan area or by state for nonmetropolitan
areas. Furthermore, three sets of SPM thresholds are computed by the housing status
of a family—as homeowners with a mortgage, homeowners without a mortgage, or
renters—to reflect differences in housing costs. Thus, while the official poverty
measure uses 48 poverty thresholds to represent families’ needs, the SPM uses
thousands.
Financial resources that are considered relevant for comparing against the measure
of need as specified in the thresholds. Financial resources to meet needs, whether in
the SPM or the official measure, are based on the sum of income of all family
members. While the official measure uses money income before taxes, the SPM
makes additional adjustments and considers a wider range of resources.
4 The purpose of the SPM was discussed in 2010 by an Interagency Technical Working Group (ITWG), organized by
the Office of Management and Budget (OMB). A link to documentation of the ITWG’s observations regarding the
SPM is available on the Census Bureau’s website at https://www.census.gov/topics/income-poverty/supplementalpoverty-measure/guidance/methodology.html.
5 For a more thorough introduction to the methods of poverty measurement, see CRS Report R44780, An Introduction
to Poverty Measurement, by Joseph Dalaker.
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Family, for the purpose of assigning thresholds and counting resources. The SPM
uses an updated approach to more explicitly take account of how household members
share resources based on their relationships, which the Census Bureau’s definition of
“family” (used in the official measure) does not capture completely.
One of the most important differences between the two measures, however, is that the SPM is
intended to be revised periodically, using improved data sources and measurement techniques as
they become available, while the official poverty measure is intended to remain consistent over
time.6 A summary of the differences is provided in Table 1.
Table 1. Differences between the Official and Supplemental Poverty Measures
Official Poverty Measure
Supplemental Poverty Measure
Resource
units
(“families”)
People related by birth, marriage, or adoption
(official Census Bureau definition of “family”).
People age 15 and older not related to anyone
else in the household are considered as their
own economic units.
People related by birth, marriage, adoption,
plus unrelated and foster children, and
cohabiting partners and their children or
other relatives (if any) are considered as “SPM
resource units” (sharing resources and
expenses together).
Needs
(thresholds)
Vary according to family size and ages of
family members.
Dollar amounts based on the cost of a
food plan for families in economic stress
in the early 1960s, multiplied by three
(with adjustments for two-person families
and individuals).
Vary according to the size and
composition of the resource unit (see
above).
Dollar amounts based on consumer
expenditure data for food, clothing,
shelter, utilities, with adjustments by
homeownership and mortgage or rental
status.
Based on most recent five years of
consumer expenditure data (not fixed at
one point and trended forward), lagged
by one year for consistency with the
income data.
Housing costs geographically adjusted for
metropolitan and nonmetropolitan areas.
Resources
Updated for inflation using the Consumer
Price Index.
No geographic cost adjustments.
Money income before taxes (includes 18
private and government sources of income,
including Social Security, cash assistance, and
other sources of cash income).
Money income (both private and government
sources) after taxes...
minus: work expenses, child care
expenses, child support paid, out-ofpocket medical expenses,
plus: tax credits (such as the Child Tax
Credit and the Earned Income Tax
Credit) and the value of in-kind benefits
(such as food and housing subsidies).
6 The official poverty measure was established by the Office of Management and Budget (OMB) in Statistical Policy
Directive 14, originally issued in 1969 (as the Bureau of the Budget’s Circular A-46) and reissued in 1978. The Census
Bureau follows this directive when publishing official poverty statistics.
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Source: Congressional Research Service summary of methodological discussion in Liana E. Fox and Kalee Burns,
The Supplemental Poverty Measure: 2020, U.S. Census Bureau, September 2021, https://www.census.gov/library/
publications/2021/demo/p60-275.html.
The Supplemental Poverty Measure: Research to
Address Limitations of the Official Poverty Measure
The SPM was developed after decades of research focused on overcoming the limitations of the
official poverty measure. These limitations are not easy to surmount, as evidenced by dozens of
alternative poverty measures developed over the years by the Census Bureau and by academia,
and the working papers and reports written about those measures.7
Criticisms of the Official Poverty Measure
Over time, the official poverty measure has faced criticism, including the following:
The official poverty thresholds are not adjusted to reflect geographic variations in
costs.
Owing to the limitations of the source data available at the time the official
measure was developed, it is based on money income before taxes; however,
most individuals pay for their basic necessities using after-tax income. This
represents a disconnection between the way needs were specified in the
thresholds (which represent a level of need) and the definition of resources
available for meeting those needs.
The official measure captures the effects of some but not all government
programs intended to provide relief for the poor because the income used in the
official measure is money income before taxes.
The programs that are captured are those that provide money income benefits
before taxes: Social Security, Supplemental Security Income (SSI),
Temporary Assistance for Needy Families (TANF), and any state or local
relief programs based on money income.
The programs that are not captured are the EITC and the Child Tax Credit,
which, despite their large effects for low-income workers with children,8 are
not considered because they are tax credits and only reflected in after-tax
income; and a host of noncash benefits such as the Supplemental Nutrition
Assistance Program (SNAP), the Special Supplemental Nutrition Program
for Women, Infants, and Children (WIC), housing subsidies, and subsidized
medical care. Many of these programs did not exist when the official
measure was developed in the 1960s.
7 Working papers related to the SPM are available on the Census Bureau’s website at https://www.census.gov/topics/
income-poverty/supplemental-poverty-measure/library/working-papers.html. Reports on the SPM and on previous
experimental poverty measures are available at https://www.census.gov/topics/income-poverty/supplemental-povertymeasure/library/publications.html. Reports examining alternative income definitions (including noncash benefits and
taking account of taxes) used in earlier poverty measurement research are available by year on the Census Bureau’s
income publications page at https://www.census.gov/topics/income-poverty/income/library/publications/cps.html.
8 See, for instance, CRS Report R44057, The Earned Income Tax Credit (EITC): An Economic Analysis, by Margot L.
Crandall-Hollick and Joseph S. Hughes.
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The official measure captures neither the needs incurred nor the resources
brought in by household members who are not related by birth, marriage, or
adoption. These include unmarried partners and their children (if any are present)
and foster children not legally adopted.
While the official measure is adjusted for overall inflation, it does not consider
the extent to which the prices of basic necessities have shifted in relation to all
goods and services. Therefore, it can be argued that the inflation adjustment used
in the official measure does not accurately reflect the purchasing power needed,
in a practical sense, to attain a standard of living comparable to that of those who
lived at the poverty line in previous decades.
Motivation for a New Poverty Measure
While there has been broad agreement among poverty scholars that these issues are drawbacks to
the official poverty measure, overcoming them has proven to be difficult. Scholars in the federal
government, universities, and private research institutions have spent decades developing
approaches to address these shortcomings and evaluating the effectiveness of those approaches.9
For example, adjusting the poverty thresholds by geographic variations in costs is difficult,
because price levels within a state can vary greatly among its different metropolitan areas, as well
as between metropolitan and nonmetropolitan areas. Numerous approaches were developed over
the years to adjust thresholds geographically, and because of a lack of comprehensive small-area
geographic detail on prices, earlier approaches were more limited in their ability to accurately
reflect cost variations within states.10 Research inquiries into the other issues listed above—
9 Three such examples, in different decades, illustrate the participation from academic researchers and federal agencies
in the research discussion:
In 1976, the Department of Health, Education, and Welfare issued a multi-volume report entitled The Measure of
Poverty: A Report to Congress as Mandated by the Education Amendments of 1974 in order to comply with Section
823 of P.L. 93-380. Authors of the volumes of this report included analysts from the University of Michigan, private
research institutions (Mathematica, Urban Systems Research and Engineering, Inc.), and federal agencies (Bureau of
Labor Statistics; Census Bureau; Department of Agriculture; Department of Health, Education, and Welfare;
Department of the Treasury; Social Security Administration). The report is reproduced on the Census Bureau website at
https://www.census.gov/library/publications/1976/demo/measure-of-poverty.html.
In 1985, a conference was held to discuss methods of computing the value of noncash benefits. See Conference on the
Measurement of Noncash Benefits, December 12-14, 1985, Fort Magruder Inn and Conference Center, Williamsburg
VA, proceedings and related technical papers available at https://www.census.gov/library/working-papers/1985/demo/
measurement-conf.html. Participants included “115 persons, including 23 from the Census Bureau.... 40 persons from
universities and nonprofit research organizations, 16 persons from interest groups and other private sector
organizations, and 36 persons from other government agencies and Congressional Committees.” See conference
proceedings, Preface, p. III.
The third example is the National Academy of Sciences Panel on Poverty and Family Assistance: Concepts,
Information Needs, and Measurement Methods, which met from 1992 to 1995 and published its report, Measuring
Poverty: A New Approach, in 1995. The panel is discussed in more detail later in this report.
10 The first Census Bureau report to adjust poverty thresholds geographically was Kathleen Short, Thesia Garner, David
Johnson, and Patricia Doyle, Experimental Poverty Measures: 1990 to 1997, U.S. Census Bureau, Current Population
Reports, P60-205, 1999. The report used a methodology recommended by a panel from the National Academy of
Sciences, incorporating indices that varied by nine census regions and by population size category within regions.
Subsequent reports (e.g., Short, Experimental Poverty Measures: 1999; U.S. Census Bureau, Current Population
Reports, P60-216, 2001) used indices based on Fair Market Rent data from the Department of Housing and Urban
Development—usually two indices by state: one for all metropolitan areas within the state, the other for all
nonmetropolitan areas within the state (if any existed). While arguably both approaches were at least a conceptual
improvement over no geographic adjustment at all, they did not capture the full range of geographic cost variation. A
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particularly the valuation of noncash benefits such as subsidized health care—proved to be just as
thorny.11
Moving Toward the SPM: Decades of Research
Multiple Series of Alternative Poverty Measures
In attempting to address the shortcomings of the official poverty measure, dozens of alternative
poverty measures were developed over multiple decades. For instance, in the 1980s the Census
Bureau began providing alternative definitions of income that subtracted taxes from income and
estimated the monetary value of noncash benefits, and showed the effects of these definitions on
estimated poverty rates, in an “R&D” series of reports.12 The approaches used in these reports for
estimating the value of noncash benefits were discussed in a conference attended by analysts from
the federal government, universities, and other research institutions.13 Eventually, as variations of
the Consumer Price Index (CPI) were developed by the Bureau of Labor Statistics, the Census
Bureau began to include poverty estimates based on those indices in the R&D series as well.14
Between 1992 and 1995, a panel from the National Academy of Sciences (NAS) met to develop
recommendations for an improved poverty measure, in response to a congressional request from
the Joint Economic Committee and funded through the Bureau of Labor Statistics, the
Department of Health and Human Services, and the Food and Nutrition Service of the U.S.
Department of Agriculture. The NAS report was published in 1995.15 Since the report’s
publication, the Census Bureau had published data on alternative poverty measures based on both
discussion of cost variations within a single state and more recent approaches to adjusting poverty thresholds is
available in Trudi Renwick, “Geographic Adjustments of Supplemental Poverty Measure Thresholds: Using the
American Community Survey Five-Year Data on Housing Costs,” SEHSD Working Paper 2011-21, U.S. Census
Bureau, July 2011, https://www.census.gov/library/working-papers/2011/demo/SEHSD-WP2011-21.html.
11 For a discussion of the complexity in counting the value of subsidized health care as income, see the presentation by
Ellwood and Summers, “Measuring Income: What Kind Should Be In?” in the proceedings from the Conference on the
Measurement of Noncash Benefits, December 12-14, 1985, Fort Magruder Inn and Conference Center, Williamsburg
VA, at https://www.census.gov/library/working-papers/1985/demo/measurement-conf.html, and the subsequent
commentary by Alan Blinder and Albert Rees.
12 See, for instance, Timothy Smeeding, Alternative Methods for Valuing Selected In-Kind Transfer Benefits and
Measuring Their Effect on Poverty, U.S. Census Bureau, Technical Paper 50, 1982, https://www.census.gov/library/
publications/1982/demo/tp-50.html; and John McNeil, Measuring the Effect of Benefits and Taxes on Income and
Poverty: 1979 to 1991, U.S. Census Bureau, Current Population Reports, P60-182RD, 1992, https://www.census.gov/
library/publications/1992/demo/p60-182rd.html. Additional R&D reports are available on the Census Bureau’s website
at https://www.census.gov/library/working-papers/1985/demo/measurement-conf.html (for the seminal papers that led
to the R&D series), and by year (along with other reports) at https://www.census.gov/topics/income-poverty/library/
publications.html, beginning with Measuring the Effect of Benefits and Taxes on Income and Poverty: 1986 (Current
Population Reports, series P60 No. 164-RD-1). Data using the alternative definitions of income were later included in
the official reports on income and poverty from 1993 to 2002.
13 Conference on the Measurement of Noncash Benefits, December 12-14, 1985, Fort Magruder Inn and Conference
Center, Williamsburg VA; proceedings and related technical papers available at https://www.census.gov/library/
working-papers/1985/demo/measurement-conf.html.
14 Initially, the CPI-U-X1 and later the CPI-U-RS were used. They were developed by the Bureau of Labor Statistics to
address the over-estimation of housing costs in the official measure’s price inflator, the CPI-U. For details on the
research to develop the CPI-U-RS, see http://www.bls.gov/cpi/cpiurs.htm.
15 Constance F. Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach, Panel on Poverty and Family
Assistance: Concepts, Information Needs, and Measurement Methods, Committee on National Statistics, National
Research Council, 1995. Available from National Academies Press online at http://www.nap.edu/catalog/4759/
measuring-poverty-a-new-approach, and on the Census Bureau website at https://www.census.gov/library/publications/
1995/demo/citro-01.html.
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the older R&D series and the newer NAS-based methodologies. Unlike the R&D series, which
focused on alternative definitions of income and applying a different index to adjust thresholds
for inflation, the NAS-based experimental measures made adjustments both to the thresholds and
the income definition, and estimated work-related expenses and medical out-of-pocket
expenses.16 Research continued, both at the Census Bureau and elsewhere, to refine the
measurement methods and use the most current data sources available.17
Developing the SPM: Consolidating the Research, and Public Comment
In 2009, the Office of Management and Budget (OMB) organized an Interagency Technical
Working Group (ITWG) for establishing a Supplemental Poverty Measure. At that point, dozens
of experimental poverty measures focusing on the various aspects of poverty measurement
discussed above had been developed. The ITWG put forth a single measure (the SPM) to
consolidate the research and emphasize not only sound concepts and methodology in the
measure’s development, but also practicality in the measure’s maintenance, computation, and
usage. The ITWG did not intend to replace the official measure, and it was expected that
refinement of both the SPM’s methodology and its data sources would continue.18 The first
Census Bureau report using the SPM was published in 2011. Technical revisions to the SPM were
implemented in 2021, for which the Census Bureau released revised 2019 and new 2020 SPM
estimates with those technical revisions in place.19
How Is the SPM Currently Computed?
As mentioned above, the SPM differs from the official poverty measure in three broad ways.
First, the measure of need is defined differently in the SPM’s poverty thresholds. Second, the
16 The R&D series of alternative poverty measures shown in the Census Bureau’s annual poverty reports, while
intended to illustrate the marginal effects of certain income types and noncash benefits on the overall poverty rate,
could be misinterpreted to imply that those alternative income definitions were intended to represent the full range of
resources available, and that the official thresholds described the level at which basic needs were fully met. The text of
the Census Bureau reports avoided such characterization and instead focused on the effects of each definition on the
overall poverty rate. In vetting the SPM, the Interagency Technical Working Group (ITWG) explicitly stated its intent
to define resources and needs consistently, echoing similar commentary in the NAS report.
17 The research (working papers and conference presentations) is published on the Census Bureau website at
https://www.census.gov/topics/income-poverty/supplemental-poverty-measure/library/working-papers.html, and on the
Bureau of Labor Statistics website at http://www.bls.gov/pir/spmhome.htm.
A review of the research into alternative methods for measuring poverty leading up to the SPM is available in CRS
Report R41187, Poverty Measurement in the United States: History, Current Practice, and Proposed Changes, by
Thomas Gabe (available to congressional clients upon request).
18 Observations from the ITWG on developing the SPM have been published on the Census Bureau’s website at
https://www.census.gov/content/dam/Census/topics/income/supplemental-poverty-measure/spm-twgobservations.pdf.
The Census Bureau submitted a notice in the Federal Register published on May 26, 2010, soliciting comments about
the SPM. The notice, feedback, and comments are available at https://www.census.gov/topics/income-poverty/
supplemental-poverty-measure/guidance/methodology.html.
19 The description of the SPM in the rest of this report reflects the latest methodological changes, but focuses on
describing the basic SPM methodology. For a list of the specific changes in 2021 and their detailed descriptions, see
page 19 of Liana E. Fox and Kalee Burns, The Supplemental Poverty Measure: 2020, U.S. Census Bureau, September
2021, https://www.census.gov/library/publications/2021/demo/p60-275.html. Further details are available in Kalee
Burns and Liana Fox, “Improvements to the Census Bureau’s Supplemental Poverty Measure for 2021,” U.S. Census
Bureau, Working Paper SEHSD-WP-2021-17, September 8, 2021, at https://www.census.gov/library/working-papers/
2021/demo/SEHSD-WP2021-17.html (hereinafter, “Burns and Fox (2021)”).
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economic resources measured in the SPM differ from those counted in the official poverty
measure. Third, the definition for “family” units used in the SPM is not the same.
In determining an individual’s poverty status, the poverty thresholds are compared with his or her
family’s economic resources. Information on relationships within the household determines
which threshold is appropriate to use and whose resources are to be compared with that threshold.
This information on family relationship and resources is measured using household surveys, and
the way it is measured is affected and limited by what is asked in the surveys.
Since 2011, the Census Bureau has produced estimates of individuals living in poverty as
measured by the SPM using the Annual Social and Economic Supplement (ASEC) to the Current
Population Survey (CPS) as the source of the family relationship and income information used to
compute poverty status. The CPS ASEC is also the survey used to produce the official poverty
estimates at the national level. Thus, the SPM poverty estimates described in this report are based
on the detail available in, and the limitations of, the CPS ASEC. Beginning in 2020, the Census
Bureau has also published SPM datasets using the American Community Survey (ACS). The
ACS has a larger sample than the CPS ASEC (and thus can provide better estimates for smaller
areas and populations than the CPS ASEC), but less detail on income and family relationships,
which require some additional adjustments to be made.20 If other surveys were to be used to
estimate SPM poverty, their limitations and advantages would affect what information could be
produced.
Definition of Need in SPM Poverty Thresholds
Goods and Their Costs
In drawing the poverty line, neither the SPM nor the official poverty measure attempted to parse
out exactly how much of every type of good or service, with corresponding prices, is needed by a
family to form an overall budget. Instead, both the SPM and the official measure used data on
families’ spending. In the case of the official measure, this was the spending related to food. The
official measure’s thresholds were based on food costs in the 1960s and food spending patterns of
families in 1955. According to a 1955 USDA food consumption survey, families spent
approximately one-third of their income on food, on average; therefore, the costs of the food
plans were multiplied by three to produce family income amounts.21
The SPM uses the costs of food, clothing, shelter, and utilities (FCSU) as measured in the
Consumer Expenditure Survey (CE).22 These items were selected because the panel considered
20 For details on the methodology of SPM estimates using the ACS, see Liana Fox, Brian Glassman, and Jose Pacas,
“The Supplemental Poverty Measure Using the American Community Survey,” U.S. Census Bureau, SEHSD Working
Paper Number 2020-09, July 20, 2020, at https://www.census.gov/library/working-papers/2020/demo/SEHSDWP2020-09.html.
21 The actual food plans took account of dietary needs by age and sex. For her purposes, Mollie Orshansky (the analyst
who developed the official thresholds) performed some computations, using 1960 census data, to translate the food
costs by age and sex into amounts by family size and composition. Furthermore, she made adjustments to the poverty
thresholds (which represent total family income, not just food costs) for two-person families and for unrelated
individuals to account for the comparatively higher fixed costs that those units face. For details, see Gordon Fisher,
“The Development of the Orshansky Thresholds and Their Subsequent History as the Official U.S. Poverty Measure,”
1992 (rev. 1997), reproduced on the Census Bureau’s website at https://www.census.gov/library/working-papers/1997/
demo/fisher-02.html.
22 The selection of FCSU as the set of basic goods and services to be included in the thresholds was discussed in
Constance F. Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach, Panel on Poverty and Family
Assistance: Concepts, Information Needs, and Measurement Methods, Committee on National Statistics, National
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them to be broadly accepted as universal needs and relatively noncontroversial. The panel did not
specify exact amounts for items within these broad categories, but rather focused on overall
spending patterns within the categories using CE data. Furthermore, the panel acknowledged that
other items would be needed by families, such as non-work related transportation, personal care
products, cleaning supplies, and the like; but rather than attempt to specify exact amounts for
these items, the panel instead allowed for “a little more”—20% of the cost of FCSU—for
miscellaneous items (that is, the threshold represents the cost of FCSU multiplied by 1.2).23
The Bureau of Labor Statistics (BLS) computes the dollar amount used as a starting point for
computing the complete set of thresholds. This is done by using the Consumer Expenditure
Survey (CE). The FCSU expenditure distribution is computed among families (called consumer
units24) with children based on CE data. BLS estimates the median FCSU by taking the FCSU
expenditure amounts among the 47th to 53rd percentiles (of consumer units with children)—and
then averaging them.25 Per recommendations from the 1995 NAS panel, that estimated median is
then multiplied by 0.83 (that is, 83%), to represent a modest level of FCSU expenditures, for
families exactly at the poverty line.26 Once that dollar amount has been computed (to represent
FCSU), it is then multiplied by 1.2 (meaning an extra 20%) to allow for miscellaneous costs, such
as for personal care products, cleaning supplies, and non-work-related transportation. This extra
Research Council, 1995, pp. 48-51, http://www.nap.edu/catalog/4759/measuring-poverty-a-new-approach. The
Consumer Expenditure Survey is a nationwide household survey conducted by the U.S. Bureau of Labor Statistics to
find out how Americans spend their money. For details, see https://www.bls.gov/opub/hom/cex/home.htm.
23 The NAS panel was careful not to recommend any one specific level, but rather suggested a range of dollar amounts
that might be considered reasonable in light of other studies of poverty. The panel discussed this approach in Chapters
1 and 2 of Constance F. Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach, Panel on Poverty and
Family Assistance: Concepts, Information Needs, and Measurement Methods, Committee on National Statistics,
National Research Council, 1995, http://www.nap.edu/catalog/4759/measuring-poverty-a-new-approach, and cited the
studies they used and the corresponding threshold amounts of those studies in Table 2-5 of that volume. In 2010, the
ITWG recommended the 33rd percentile of FCSU expenditures because it represented the midpoint of the NAS panel’s
range. See “Observations from the Interagency Technical Working Group on Developing a Supplemental Poverty
Measure” at https://www.census.gov/content/dam/Census/topics/income/supplemental-poverty-measure/spmtwgobservations.pdf.
24 Consumer units are defined somewhat differently from the way families are typically defined in Census Bureau
products; consumer units include non-relatives who make joint expenditure decisions. Families in SPM estimates also
include those non-relatives. Further details are provided in the Consumer Expenditure Survey glossary at
https://www.bls.gov/cex/csxgloss.htm and in the “Family Units in the SPM” section of this report.
25 Because the expenditures are based on a survey sample, using 47 th to the 53rd percentiles provides more families in
the sample with which to approximate the median expenditures (i.e., the 50th percentile). Before 2021, a similar
approach was used to approximate the 33rd percentile, by using families between the 30th and 36th percentiles (see
Thesia I. Garner, “Supplemental Poverty Measure Thresholds: Laying the Foundation,” Bureau of Labor Statistics,
Division of Price and Index Number Research, December 29, 2010, https://www.bls.gov/pir/spm/
spm_pap_thres_foundations10.pdf ). For a discussion of the threshold estimation methods centered around the median
rather than the 33rd percentile, see Liana E. Fox and Thesia I. Garner, “Moving to the Median and Expanding the
Estimation Sample: The Case for Changing the Expenditures Underlying SPM Thresholds,” U.S. Census Bureau,
Working Paper SEHSD-WP2018-02, February 12, 2018, https://www.census.gov/library/working-papers/2018/demo/
SEHSD-WP2018-02.html (hereinafter, “Fox and Garner (2018)”).
26 According to Fox and Garner (2018):
The ITWG recommended that SPM thresholds be based on the range of FCSU expenditures around
the 33rd percentile range. The justification for this was that the value in this percentile range was
equal to 78 to 83 percent of the median. (p. 10)
The figure of 78% to 83% of the median of FCSU expenditures was recommended by the NAS panel in 1995. In
establishing the SPM, the ITWG instead used the 33rd percentile of FCSU expenditures, which it determined to be
comparable to the figure recommended by the NAS panel. The recent revisions to the SPM revert back to 83% of the
median FCSU expenditures.
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20% is included to reflect costs that are necessary but are not otherwise reflected in FCSU
expenditures. Determining the starting dollar amount is the first step in computing the thresholds;
the next step is adjusting that amount by homeownership or rental status.
Adjustment of the Thresholds by Homeownership or Rental Status
Three sets of poverty thresholds are used in the SPM: one for homeowners with a mortgage,
another for homeowners without a mortgage, and a third for renters. These differing sets of
thresholds based on tenure (ownership or rental status) reflect that housing costs can differ greatly
among these three groups. Housing costs make up roughly 30% to 45% of the expenditures
represented in the SPM thresholds; for homeowners without mortgages the housing-related
expenditures are at the lower end of that range, while renters and homeowners with mortgages
tend toward the upper end of the range.27 Moreover, these groups tend to differ demographically
as well. Homeowners without mortgages tend to be older but also have lower incomes on average
than homeowners with mortgages. Homeowners with mortgages are younger, have greater
income, and are more likely to be raising children. Renters have lower income than the
homeowner groups but also tend to be younger and are more likely to be raising children than
homeowners without mortgages.
Like the other costs used in the SPM thresholds, BLS obtains the housing costs using data from
the Consumer Expenditure Survey. That survey provides information on housing costs by tenure
for the United States as a whole, but it does not provide the level of geographic detail needed to
perform geographic adjustment.28 The geographic adjustment, and all subsequent adjustments to
the thresholds, are performed by the Census Bureau.
Adjustment of the Thresholds by Geographic Variations in Housing Costs
The SPM adjusts for geographic differences in housing costs. It uses the American Community
Survey’s information on median rental costs in a geographic area and compares it to the national
median rent.
To obtain comparable rent costs, a standard rental unit—two bedrooms with complete kitchen and
plumbing facilities—is used. The median gross rent (including utility costs), based on ACS fiveyear data, is used in the comparison. Indices are computed by state: one index for each
metropolitan area within the state, and an index representing all nonmetropolitan areas within the
state.29 Once the indices are computed, a portion of the reference threshold (the part representing
27 These percentages reflect the latest revisions to the SPM methodology, including the removal of telephone service as
a housing utility; for details, see Thesia I. Garner and Juan D. Munoz Henao, “Controlling for Prices Before Estimating
the SPM Thresholds and the Impact on SPM Poverty Statistics,” Bureau of Labor Statistics, April 19, 2018, prepared
for the 2018 Society of Government Economists Conference, Washington DC, https://www.bls.gov/pir/spm/gnr-mzfcsm-4-19-18.pdf.
28 The costs of FCSU are multiplied by 1.2 to allow for miscellaneous costs after the housing expenditure portion is
adjusted by homeownership or rental status (to create three thresholds), but before the housing portions of the
thresholds are adjusted geographically. The thresholds (their entire amounts) are scaled by family size and composition
after that geographic adjustment. For details, see Thesia I. Garner, “Supplemental Poverty Measure Thresholds: Laying
the Foundation,” Bureau of Labor Statistics, Division of Price and Index Number Research, December 29, 2010,
https://www.bls.gov/pir/spm/spm_pap_thres_foundations10.pdf.
29 In some cases, small metropolitan areas within a state may be aggregated into an “other metropolitan” category to
protect respondents’ confidentiality; see Section V of Trudi Renwick, “Geographic Adjustments of Supplemental
Poverty Measure Thresholds: Using the American Community Survey Five-Year Data on Housing Costs,” SEHSD
Working Paper 2011-21, U.S. Census Bureau, July 2011, https://www.census.gov/library/working-papers/2011/demo/
SEHSD-WP2011-21.html.
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housing costs) is multiplied by them to produce SPM thresholds geographically adjusted for
housing costs.30
Adjustment of the Thresholds by Family Size
The thresholds are adjusted for family size and composition to allow that costs increase as family
size increases, but also that there are economies of scale—efficiencies can be obtained by sharing
resources. The mathematical relationship that describes how the thresholds are adjusted by family
size and composition is called the equivalence scale.
In the official measure, the equivalence scale is not computed explicitly, but rather driven by the
food plan costs upon which the official thresholds were based. In contrast, the SPM uses
mathematical formulas to adjust the thresholds by family size. The formulas are used to compute
scale factors. A scale factor is a number that is multiplied by a standard dollar amount,
representing the equivalent of one adult’s needs, in order to increase the threshold proportionately
to reflect the costs incurred by the increase in family size. The scale factors are computed using
the number of adults and children in the family as inputs, along with important parameters.31
Adjustment of the Thresholds for Changes over Time
The SPM uses a different approach from the official measure in adjusting the threshold amounts
over time. The official thresholds are adjusted annually for inflation using the CPI-U; no other
adjustments are made. The SPM thresholds, in contrast, are recomputed based on five recent
years of data on families’ expenditures on FCSU, obtained from the Consumer Expenditure
Survey, with a one-year lag from the most recent year, to better match the reference period of the
CPS ASEC income data. This approach differs conceptually from the official measure’s inflation
adjustment in three ways:
1. Instead of directly factoring in a measure of overall inflation, the SPM includes
the effects of inflation through the amounts that families spent on FCSU (as
reported in the Consumer Expenditure Survey32).
30 The remaining part of the threshold is not adjusted for geographic differences in costs. Unlike for housing costs,
price data on the other goods in the SPM threshold are not available with sufficient statistical reliability for small
geographic areas throughout the entire country. The CPI, which provides price indices on a variety of goods and
services, is published for 26 metropolitan areas, and for the four regions of the country (Northeast, Midwest, South, and
West) by population size groups, but is not published for every metropolitan area throughout the country. For details,
see https://www.bls.gov/cpi/cpifact8.htm.
31 Three parameters are used in the computation: (1) Children are assumed to incur fewer costs than adults. The
weighting factor for the costs incurred by an additional child in the family is set to 0.5, or half the costs incurred by an
additional adult (with an important exception noted below). (2) The first child in a single-adult family incurs greater
expenses than the first child in a two-adult family. The weighting factor for the first child in a single-adult family is set
to 0.8, or 80% of the costs incurred by the adult. Additional children thereafter are considered to incur half the costs of
the adult (weighting factor of 0.5), just like their counterparts in multiple-adult families. (3) Even accounting for
differing costs between adults and children, costs do not stay the same as family size increases. Costs increase, but not
necessarily by the same amount for each additional person (even if the additional members are all adults), because
family members share resources. The arithmetic used to incorporate the way family members incur costs and share
resources is discussed in the methodological appendix of Liana E. Fox and Kalee Burns, The Supplemental Poverty
Measure: 2020, U.S. Census Bureau, September 2021, https://www.census.gov/library/publications/2021/demo/p60275.html.
The scale factor methodology is based on the research of Dr. David Betson of Notre Dame; see, for example, David M.
Betson, “Alternative Estimates of the Cost of Children from the 1980-86 Consumer Expenditure Survey,” Institute for
Research on Poverty Special Report no. 51, December 1990. http://www.irp.wisc.edu/publications/sr/pdfs/sr51.pdf.
32 Five years of Consumer Expenditure Survey data are used; a price index is applied to ensure the FCSU amounts from
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2. Price changes on goods and services other than FCSU are not considered
directly—only families’ spending on FCSU. Families’ FCSU spending,
moreover, is not held to be any fixed percentage of families’ overall income
(unlike the official measure, where the thresholds were fixed at three times the
cost of food in the 1960s and updated for overall inflation since then). That
means if FCSU spending grows as a portion of family income, the SPM
thresholds will rise to reflect that spending, even if family income does not rise.
Conversely, if family income rises, and a greater portion of family income were
spent on goods other than FCSU, the SPM thresholds would reflect only the
changes in FCSU spending.
3. The SPM thresholds are set at approximately 83% of the median of FCSU
spending, by ranking the FCSU spending across all families with children in the
Consumer Expenditure Survey sample. This is different from setting a fixed
dollar amount in a single time period and adjusting for inflation thereafter. The
SPM thresholds are computed so that even if the distribution of family
expenditures changes over time, more than half of all families will have reported
spending more on FCSU than is allotted in the SPM thresholds.33
Additionally, the ITWG intended for the SPM methodology to be updated periodically, as poverty
measurement research identifies ways to improve the measure and as new data sources become
available. The official thresholds, on the other hand, are updated for inflation but no changes to
the overall approach to computing them have been planned: the Census Bureau continues to
follow OMB’s Statistical Policy Directive 14.
Definition of Resources in SPM Poverty Thresholds
The SPM takes account of a wider array of resources than the official measure, and it also takes
account of taxes and expenses in a way the official measure does not. The official poverty
measure uses money income before taxes as its definition of resources. While this definition was
based on the best data available when the official measure was developed in the 1960s, it is
inconsistent with the poverty thresholds as they were conceptually defined. The thresholds were
constructed to represent the total amount of money families had available to spend; the food costs
as identified by the USDA food plans and as consolidated by Orshansky into families of different
sizes and compositions were meant to reflect the fraction of a family’s money that was available
to be spent on food. The degree of privation represented by the official thresholds was
characterized by the food plans’ effectiveness at providing a “fair or better” diet, but not
necessarily a good diet, while keeping the food costs low.34
that survey are all expressed in terms of the same year. Before 2020, the index used was the CPI-U; beginning with
2020 data, the FCSUti CPI-U is used. For details, see https://www.bls.gov/pir/spm/spm_2019re_changes.htm.
33 This method of setting the thresholds at approximately 83% of the median has implications for interpreting SPM
estimates, and is discussed further in the section “Nature of the SPM: a Relative or an Absolute Measure?”
34 The distinction between “good” and “fair or better” was explained by Betty Peterkin and Faith Clark, “Money Value
and Adequacy of Diets Compared with the USDA Food Plans,” Family Economics Review, September 1969, p. 8:
“Diets were considered good if they provided the recommended allowances (1963) for all nutrients, and fair or better if
they provided at least two-thirds of the allowances.” They presented results of a 1965 survey of urban families that
indicated less than 50% of families on the Economy Food Plan had a fair or better diet (implying at least 50% did not),
while less than 10% of the families on the plan had a good diet; https://archive.org/details/
familyeconomicsr6251inst_48.
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The SPM was designed to define the resources available to a family consistently with the needs
specified in the thresholds (FCSU plus a bit extra for miscellaneous expenses, such as non-work
related transportation and personal care). The items used to construct the income measure are
presented below, and are discussed more fully in the Census Bureau’s report on the SPM.35
Money Income and Other Resources
Money Income
The CPS ASEC, which is the data source used by the SPM to identify most resources, asks about
18 types of income. These include government cash benefits—such as Social Security,
Unemployment Insurance, Workers’ Compensation, Supplemental Security Income, public
assistance received in the form of cash (such as Temporary Assistance for Needy Families)—or
child support received.36 Not all income sources included in the CPS ASEC are taxable income.
Estimated Value of In-Kind Benefits
Unlike the official measure, the SPM includes estimates of the monetary value of in-kind
benefits, such as for food and subsidized housing, in the measure of income. These benefits are
relevant because they are used to provide the items specified in the poverty thresholds. The SPM
incorporates estimated values for several in-kind benefits:
Supplemental Nutrition Assistance Program (SNAP). The SPM includes SNAP in
its resource definition because families use it to help meet their food needs—and
food costs are included in the SPM thresholds. CPS ASEC asks respondents whether
anyone in the household received SNAP, and if so, what the face value of the benefits
was. Amounts for the entire household are prorated to the family units as defined for
the SPM when the two types of units are not identical.37
Special Supplemental Nutrition Program for Women, Infants, and Children
(WIC). The SPM includes WIC in its resource definition.38 However, the CPS ASEC
35 Liana E. Fox and Kalee Burns, The Supplemental Poverty Measure: 2020, U.S. Census Bureau, September 2021,
https://www.census.gov/library/publications/2021/demo/p60-275.html. Methodological details are provided in the
appendix of that report.
36 A list of income sources measured by the CPS ASEC, and other details, are provided in Emily A. Shrider, Melissa
Kollar, Frances Chen, and Jessica Semega, Income and Poverty in the United States: 2020, U.S. Census Bureau,
September 14, 2021, Appendix A, “Estimates of Income,” at https://www.census.gov/content/dam/Census/library/
publications/2021/demo/p60-273.pdf#page=33.
37 In the CPS, a household includes all persons residing in the same housing unit, regardless of family relationship.
38 According to Burns and Fox (2021):
On the resource side, the valuation of the Special Supplemental Nutrition Program for Women,
Infants and Children (WIC) changed from a national average value to state-varying values. This
change allows for state-level changes to WIC to be reflected in the SPM. Program receipt for WIC
is asked in the Current Population Survey Annual Social and Economic Supplement (CPS ASEC),
but the dollar value of WIC is not asked. Therefore, since its inception, the SPM has estimated the
number of WIC recipients in an SPM unit, assumed 12 months of WIC receipt, and assigned the
annual value using the national monthly average WIC benefit as reported by the Food and Nutrition
Service of the USDA. As information regarding pregnancy and breast-feeding status is not
collected in the CPS ASEC, individuals are given an average value of WIC benefits rather than
attempting to impute participant types. The only change to the current resource side of the SPM
methodology was to use state-varying averages rather than national averages. Preliminary
estimation of this new methodology was detailed in work by Fox and Wilson (2020).
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does not ask respondents how much in WIC benefits they received, only whether they
received benefits at all. For the purposes of estimating benefits, the Census Bureau
assumes 12 months of participation when the respondent reports having received
them. Average amounts by state are then applied to the participants.39 This
assumption may overestimate the value of benefits received. To compute the benefit
amounts received, the Census Bureau refers to WIC program information from the
USDA, and uses age information reported in the CPS ASEC to determine which
household members receive benefits.
School Lunch. Subsidized school lunches are included in the SPM resource
definition, and beginning with the 2020 SPM estimates, they are also included in the
thresholds.40 The COVID-19 pandemic and associated school closures, virtual
schooling, and hybrid schools, in tandem with the federal government’s policy
changes around school lunch provisions during the pandemic, prompted the Census
Bureau to use an alternative approach for estimating school lunch benefit amounts in
2020.41
Subsidized housing. Because the SPM includes shelter costs in the thresholds, the
SPM includes subsidized housing in its resource definition. The Census Bureau
estimates the “market rent” value for the housing unit and subtracts from that an
estimated amount paid by the tenant. The difference is the estimated housing subsidy.
Market rent is estimated using administrative data from the Department of Housing
and Urban Development (HUD), and the amounts paid are estimated using HUD
program rules and income information on the CPS ASEC. For computing poverty
status under the SPM, the estimated subsidies are capped at the housing portion of the
threshold minus the estimated amount paid by the tenant—housing subsidies can free
up resources for a family to purchase other goods, but housing benefits cannot be
used to purchase other goods and services once the family’s housing needs have been
met.
Home energy assistance. Utility costs are included in the SPM thresholds; therefore,
home energy assistance is included in the SPM resource definition. The CPS ASEC
asks about energy assistance received for the entire year, and the SPM uses this data.
39 The use of state-level averages is a new development applied to 2020 data (from the 2021 CPS ASEC). As explained
in an earlier research paper by Liana Fox and Danielle Wilson, “Using state WIC averages, rather than the national
WIC average, does not meaningfully change SPM rates, even for the most highly affected subgroup of WIC recipients.
While moving to state-varying means could potentially allow for examination of state-level policy changes in the
future, they have little impact on poverty rates overall”; Liana Fox and Danielle Wilson, “Impact of Using State
Average WIC Values in the Supplemental Poverty Measure,” U.S. Census Bureau, Working Paper 2020-16, October 1,
2020, https://www.census.gov/library/working-papers/2020/demo/SEHSD-WP2020-16.html.
40 Because information on a child’s participation in the school lunch program is not available in the Consumer
Expenditure Survey, an estimate is made (using data from the CPS ASEC) for whether a child would participate in the
school lunch program. For those estimated to participate, amounts are assigned using state-level school lunch payment
data. Details are available in Thesia I. Garner and Marisa Gudrais, “Alternative Poverty Measurement for the U.S.:
Focus on Supplemental Poverty Measure Thresholds,” Bureau of Labor Statistics Working Paper No. 510, September
2018, https://www.bls.gov/pir/spm/alt-pov-spm-wp-510.pdf.
41 The modified approach reflected that school closures, virtual schooling, and hybrid models affected how school
lunches were provided. Families who received SNAP also received school lunch subsidies on their electronic benefit
cards, while those who did not receive SNAP received separate benefit cards; these practices made it harder to separate
out SNAP amounts from school lunch amounts. For a summary of the revised estimation methods, see Fox and Burns
(2021), pp. 21-22. For details see Em Shrider, “Alternative School Lunch Valuation in the CPS ASEC During COVID19,” U.S. Census Bureau, Working Paper SEHSD-WP-2021-20, September 2021, at https://www.census.gov/library/
working-papers/2021/demo/SEHSD-WP2021-20.html.
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However, respondents may have difficulty reporting exact amounts of energy
assistance when Low Income Home Energy Assistance Program (LIHEAP) payments
are made directly to landlords or energy providers. The manner by which the
assistance is provided can vary by state.
Expenses Subtracted from Income
Families typically pay for their needs using after-tax income; for that reason, the SPM uses aftertax income in its definition of resources. However, the CPS ASEC does not ask respondents about
taxes paid. In order to compute after-tax income, the Census Bureau estimates taxes using a
model. The CPS ASEC income and demographic data are used to estimate the probability of
families’ filing statuses (such as married filing jointly or married filing separately), having
itemized deductions, and having capital gains, using the distribution of those variables as found in
IRS data (Statistics of Income, or SOI).42
Work-Related Expenses Other than Child Care
Money that families spend as part of going to work is not available for meeting the needs
specified in the SPM thresholds. Therefore, those expenses must be subtracted from income in
order for the SPM’s resource definition to be consistent with the thresholds. A flat amount,
representing weekly work-related expenses other than child care, is multiplied by the number of
weeks worked for every working family member. The flat amount is based on 85% of median
weekly work expenses as reported in the Survey of Income and Program Participation. Apart
from child care, most work expenses are linked to transportation to and from one’s job. Work
expenses—particularly commuting costs—can vary a great deal between geographic areas and
across families in the same area. The NAS panel that developed recommendations for an
improved poverty measure (mentioned above) observed that when making choices about
residence and employment, families weigh the advantages of more expensive housing close to
work (with lower commuting costs) versus less expensive housing further from work (with higher
commuting costs).43 The panel was therefore unable to recommend a method that accurately
reflected the variations in work expenses across families and geographic areas that was
substantially more precise than assigning a flat amount across families based on number of weeks
worked. However, research into improving the measure of these work-related expenses is
ongoing.44
42 Details on the tax model are available in Amy O’Hara, “Tax Variable Imputation in the Current Population Survey,”
2006 IRS Research Conference, June 14-15, 2006, Washington, DC, https://www.irs.gov/pub/irs-soi/06ohara.pdf; and
Amy O’Hara, “New Methods for Simulating CPS Taxes,” U.S. Census Bureau Technical Paper, 2004,
https://www.census.gov/library/working-papers/2004/demo/oharataxmodel.html. Subsequent research on the effects of
CPS questionnaire changes on the tax model is available in Bruce H. Webster Jr., “Evaluating the Use of the New
Current Population Survey’s Annual Social and Economic Supplement Questions in the Census Bureau Tax Model,”
Income Statistics Branch, U.S. Census Bureau, September 2011, https://www.census.gov/library/working-papers/2011/
demo/SPM_Tax_Model_paper.html.
43 Constance F. Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach, Panel on Poverty and Family
Assistance: Concepts, Information Needs, and Measurement Methods, Committee on National Statistics, National
Research Council, 1995, pp. 242-243, http://www.nap.edu/catalog/4759/measuring-poverty-a-new-approach.
44 Research papers on work-related expenses and child care are published on the Census Bureau’s website at
https://www.census.gov/topics/income-poverty/supplemental-poverty-measure/library/working-papers/topics/workrelated.html.
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Child Care Expenses
If child care is needed in order for a family member to work, then the additional resources
brought in by that worker do not represent the full amount earned—child care costs must be
subtracted to reflect the available money for purchasing the needs identified in the SPM
thresholds. Respondents to the CPS ASEC are asked whether child care expenses are incurred
while the parents are working, and if so, how much they are. When computing resources for the
SPM, the sum of child care expenses and other work-related expenses are capped at the income of
the lower-earning parent (so that for determining poverty status, expenses cannot exceed the
amount brought in by working).
Medical Out-of-Pocket Expenses (MOOP)
As part of the section of the CPS ASEC questionnaire that asks about health insurance coverage,
respondents are asked to report the amount of their health insurance premiums and other medical
care costs that they paid out-of-pocket. These costs, called MOOP, are subtracted from income
when computing available resources relevant for meeting needs defined in the SPM.
Poverty measurement scholars debated for decades about the approach to use when taking
account of medical costs in relation to poverty. On one hand, poor health can affect people’s
quality of life, affect their ability to earn more income, and change their spending habits. Thus, it
affects people’s economic behavior, which, it can be argued, is relevant for measuring poverty.
On the other hand, the causes of poor health are not always linked to monetary factors. Health
issues are often caused by physical phenomena unrelated to economics, which can lead to the
argument that health care should not be included in a poverty measure but rather considered as a
separate indicator of well-being. Moreover, the choices about whether to be insured and what
kind of insurance to purchase heavily influence levels of spending on health care, both for the
healthy and the sick. At the same time, it seems incongruous to consider a person who is healthy
(and who therefore does not need expensive health care) as poorer than a sick person who
receives expensive health care but otherwise has the same resources as the healthy person.45
To resolve this conundrum, the SPM does not include health expenses as part of the threshold—as
medical needs vary greatly and not always predictably. Instead, it subtracts MOOP from the
resource definition, as those resources are considered to be necessary expenditures (if and when
they are incurred) and are not available to be spent on the needs defined in the thresholds. This
approach, moreover, does not include the value of health care dispensed by insurance providers or
by public coverage. It only considers the portion spent out-of-pocket by patients and their
families. However, research on how to develop a health-inclusive poverty measure is ongoing.46
45 David Ellwood and Lawrence Summers discussed this incongruity in “Measuring Income: What Kind Should Be
In?” presented at the Conference on the Measurement of Noncash Benefits, December 12-14, 1985, Fort Magruder Inn
and Conference Center, Williamsburg VA; proceedings and related technical papers available at
https://www.census.gov/library/working-papers/1985/demo/measurement-conf.html. The NAS panel discussed medical
care needs and resources in Constance F. Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach,
Panel on Poverty and Family Assistance: Concepts, Information Needs, and Measurement Methods, Committee on
National Statistics, National Research Council, 1995, pp. 223-237, http://www.nap.edu/catalog/4759/measuringpoverty-a-new-approach.
46 See, for instance, John Creamer, “Incorporating Health Insurance in Poverty Measurement: Implementing a Health
Inclusive Poverty Measure in the United States,” U.S. Census Bureau, Working Paper SEHSD-WP-2021-26, December
2021, at https://www.census.gov/library/working-papers/2021/demo/SEHSD-WP2021-26.html.
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Child Support Paid
Because child support received is a form of money income and is counted as a resource in the
SPM, any child support paid to another household would be double-counted if it were not
subtracted from income. The person paying child support, moreover, cannot use the amounts paid
to meet the needs specified in the SPM thresholds. The CPS ASEC includes child support
received in its measure of money income, and because of a series of questions added in 2010 it
now asks respondents whether child support is paid to other households and the amounts thereof.
The SPM resource measure therefore includes child support received (if any) and subtracts child
support paid (if any).
Family Units in the SPM
The SPM captures how some nonrelatives share needs and resources in a way the official poverty
measure does not. The official measure defines a family as all persons related by birth, marriage,
or adoption who reside in the same housing unit. That definition treats each partner in unmarried
cohabiting couples as separate units. It also excludes unrelated individuals under age 15, such as
foster children. Because the surveys on which poverty estimates are based do not ask income
questions of persons under age 15, any children under that age who cannot be matched with an
older person’s income have an indeterminate poverty status and are excluded from tabulation
totals.
The SPM defines family units—termed “SPM resource units”—differently from the official
measure, using the detailed information on relationships among household members gathered by
the CPS ASEC. This relationship detail includes the ability to identify foster children and,
because of survey improvements in the 1990s and 2000s, cohabiting couples.47 The SPM treats
cohabiting unmarried couples and any children they may have as part of the same unit and assigns
thresholds and computes family income accordingly. This is done to more accurately reflect the
way that people within households incur expenses and share resources to meet them.48 Similarly,
all foster children under age 22 are included in the SPM resource units. Not only do these changes
reflect recent demographic trends,49 but they also coordinate broadly with the “consumer unit”
concept in the Consumer Expenditure Survey (CE).50
47 The CPS ASEC is the source of income data for both the SPM and the annual national reports based on the official
measure; the SPM uses household relationship information differently from the official measure. Information about
unmarried partners has been collected in the CPS ASEC since 1996; in 2007 a question was added to identify couples
in which neither partner is the householder. For details, see Rose Kreider, “Improvements to Demographic Household
Data in the Current Population Survey: 2007,” U.S. Census Bureau, Housing and Household Economic Statistics
Division Working Paper, March 3, 2008, https://www.census.gov/population/www/documentation/twps08/twps08.pdf.
48 The NAS panel discussed the treatment of cohabiting couples in Constance F. Citro and Robert T. Michael, eds.,
Measuring Poverty: A New Approach, Panel on Poverty and Family Assistance: Concepts, Information Needs, and
Measurement Methods, Committee on National Statistics, National Research Council, 1995, pp. 301-307,
http://www.nap.edu/catalog/4759/measuring-poverty-a-new-approach.
49 In 1967, approximately three years after the official poverty measure was developed, only 0.4% of adults 18 and
older lived with an unmarried partner, while 70.3% lived with a spouse. By 2016, those living with an unmarried
partner had risen to 7.4% of adults, while those living with a spouse had fallen to 51.2% (U.S. Census Bureau, Current
Population Survey, 1967-2016 Annual Social and Economic Supplements). The rise suggests that the effect of
unmarried partnerships on poverty statistics is no longer negligible. For historical data on the living status of adults, see
https://www.census.gov/data/tables/time-series/demo/families/adults.html, particularly Table AD-3 at
https://www2.census.gov/programs-surveys/demo/tables/families/time-series/adults/ad3.xlsx.
50 A glossary of concepts used in the Consumer Expenditure Survey is available at https://www.bls.gov/cex/
csxgloss.htm.
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Still excluded from SPM tabulations, however, are members of the Armed Forces living in
barracks, the incarcerated population, residents of nursing homes, other institutionalized persons,
and the homeless population. These individuals are not eligible for interview in the CPS, as its
primary purpose is to measure employment among the civilian noninstitutional population.51
Use of the SPM
As mentioned earlier, the ITWG never intended for the SPM to replace the official poverty
measure or to fulfill administrative purposes. It supplements the official measure by allowing for
analyses of the low-income population that would not otherwise be possible. Particularly visible
and of possible relevance to Congress are the effects that taxes and tax credits, noncash transfer
programs, and work-related and medical expenses have on poverty. The SPM also highlights
differences in the demographic profile of those identified as poor.52 Even with improved visibility
into those areas, however, the SPM has important limitations to be considered.
Insights Obtainable from the SPM
Effects of Transfer Programs, Taxes, Tax Credits, and Expenses
The official poverty measure captures only those government benefits that are paid in cash. This
includes the largest government transfer program, Social Security, though it excludes Medicare.
However, in terms of programs targeted to lower income people and families, the official measure
excludes noncash medical, food, and housing benefits as well as benefits paid through the tax
code. Over time, means-tested benefits paid in noncash forms or through the tax code have grown
to account for most of what the federal government spends on low-income assistance. To
illustrate, in terms of cash benefits, in FY2020 the federal government spent $4.8 billion on
veterans’ pensions, $5.4 billion on TANF cash assistance, and $63.3 billion on Supplemental
Security Income (SSI). These cash benefits are included in both the official poverty measure and
the SPM. However, the federal government also spent a total of $85.3 billion on refundable tax
credits, $132.2 billion on food assistance, and $61.1 billion on housing, benefits that are captured
only in the SPM.53
Figure 1 illustrates the impact of various resource components on the number of people identified
as poor using the SPM. Data from both 2020 and 2019 are included because many policy changes
were implemented in 2020 due to the COVID-19 pandemic and other circumstances, and these
policy changes are reflected in the SPM estimates. Bars pointing left (negative) indicate the
number of people kept out of the population identified as poor by the SPM’s treatment of that
51 For details, see U.S. Census Bureau, Current Population Survey: Design and Methodology, Technical Paper 77,
October 2019, https://www2.census.gov/programs-surveys/cps/methodology/CPS-Tech-Paper-77.pdf.
52 The difference in family unit definitions between the official measure and the SPM also has an effect on poverty
rates. The SPM family unit definition, and its accompanying changes to family income and the assignment of
thresholds, tends to lower the number and percentage of people classified as poor. This effect occurs even without
including the complete array of changes to the resource definition that distinguish the SPM from the official measure,
or the use of SPM threshold adjustments. Using SPM family units instead of the official measure’s family designations
reduced the poverty rate estimate for 2007 by one percentage point. For details, see Kathleen Short, “Poverty Measures
that Take Account of Changing Living Arrangements and Childcare Expenses,” paper presented at the August 2009
Annual Meeting of the American Statistical Association Section on Social Statistics, Washington DC,
https://www.census.gov/library/working-papers/2009/demo/short-01.html.
53 Federal spending levels are from CRS Report R46986, Federal Spending on Benefits and Services for People with
Low Income: FY2008-FY2020, by Patrick A. Landers et al., Table 2. The refundable tax credit figure cited above
includes the refundable portions of the Earned Income Tax Credit and the Additional Child Tax Credit.
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resource component. The bars pointing right (positive) indicate the number of people added to the
estimated poor population by the SPM’s treatment of the component. These data show how the
population estimated to be poor would change if the SPM omitted a particular component (either
by subtracting resources, or failing to subtract taxes and expenses) but do not take into account
any behavioral changes people would make in the absence of any one program, tax, credit, or
expense. Furthermore, the data illustrate changes to the poverty population estimate with each
component considered in isolation. People are often affected by multiple resource components;
therefore, the numbers represented by separate bars should not be added together.
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Figure 1. The Effects of Each Transfer,Tax, or Expense on the Number of People
Identified as Below Poverty Using the SPM: 2020 and 2019
Numbers of people in millions
Source: Congressional Research Service, using data from Table A-7 from Liana E. Fox and Kalee Burns, The
Supplemental Poverty Measure: 2020, U.S. Census Bureau, Current Population Reports, P60-275, September 2021, p.
35, https://www.census.gov/library/publications/2021/demo/p60-275.html.
Notes: Numbers of people represent the estimated change in the population identified as poor if the SPM’s
resource definition were changed to exclude or include the resource component labeled at left. This can be
thought of as the marginal impact that each resource or expense had on the population below poverty in 2019
and 2020. Because people often are affected by more than one of the resource components listed, cumulative
effects of multiple resources cannot be computed by summing the bars. The impact on the estimated number of
poor was computed for each component in isolation, leaving all else equal.
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Economic impact/stimulus payments were distributed in 2020 but not in 2019. Child care expenses are included
in work expenses.
SNAP: Supplemental Nutrition Assistance Program
SSI: Supplemental Security Income
TANF: Temporary Assistance for Needy Families
LIHEAP: Low Income Home Energy Assistance Program
WIC: The Special Supplemental Nutrition Program for Women, Infants, and Children
FICA: Federal Insurance Contributions Act tax (payroll tax for Social Security and Medicare)
MOOP: Medical out-of-pocket expenses
Comparison of Impacts among Resource Components
Social Security, along with SSI, TANF, and other cash welfare assistance; Unemployment
Insurance; child support received; and Workers’ Compensation, are money income sources that
are included in both the official poverty measure and the SPM. Of these income sources, Social
Security has the biggest impact on the number of persons kept out of poverty according to the
SPM (26.5 million persons in 2020). While it was designed to be a universal program and not
targeted specifically to the poor, it has a large antipoverty effect nevertheless. While most of those
kept above poverty by Social Security were ages 65 and older (18.5 million), a substantial
minority were younger: 6.9 million were age 18 to 64, and 1.1 million were children under age
18. Some of those in the younger age groups are Social Security recipients themselves because of
a disability, but others were kept out of poverty because an older family member received it.
Unemployment Insurance, as noted above, is included in both the official measure and the SPM.
This resource component became more salient in 2020 compared with 2019, as a result of the
policy responses to the COVID-19 pandemic. In 2019, approximately 0.5 million persons were
kept out of poverty by this program according to the SPM. That figure rose to 5.5 million in 2020.
The remaining resource components shown in Figure 1 are not included in the official poverty
measure but are included in the SPM. Of these, none individually have as large an impact on the
estimated poor population as Social Security. However, the rankings of the remaining
components according to their relative impact on poverty shifted between 2019 and 2020. Those
with the most impact in 2020 were refundable tax credits. For clarity, economic stimulus
payments, which were paid in 2020 but not in 2019, accounted for 11.7 million persons kept out
of poverty. Other refundable tax credits accounted for 5.3 million persons. As was noted earlier,
these estimates are not additive: some persons likely received both types of credits and as a result
may be included in each of those estimates.
Other impactful resource components include MOOP (with 5.0 million persons added to the
poverty population once those expenses are taken into account); work expenses including child
care (2.5 million added to the poverty population, on the margin); and FICA (2.0 million added to
the poverty population, on the margin). SNAP and school lunch underwent changes to how they
were administered as a result of the pandemic. Combined, these programs are estimated to have
kept 3.2 million persons out of the poor population in 2020.
Differences in the Demographic Profile of the Poor
As seen above, people can be affected by multiple resource components considered in the SPM.
As a result, the profile of the poor population as identified by the SPM is different from that
identified by the official poverty measure. Fewer children are identified as poor in the SPM
because many government assistance programs, such as WIC, TANF, and the Additional Child
Tax Credit (ACTC), are targeted toward families with children.
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For the first time, in 2020 fewer working-age adults were classified as being in poverty under the
SPM than under the official measure; before 2020 the reverse had been true. Persons and families
received stimulus payments in 2020 in the form of refundable tax credits; those eligible also
received greater amounts of unemployment insurance than in previous years. Refundable tax
credits are not counted as resources in the official measure, but they are counted in the SPM. As a
result, the stimulus payments raised families’ incomes as measured under the SPM but not under
the official measure.54 Unemployment insurance payments are received in the form of cash and as
such are counted as income under both poverty measures; however, cohabiting couples and their
children, and foster children under age 22, are counted as family members under the SPM but not
under the official measure. Thus, while unemployment insurance is included in both measures, its
antipoverty effects are measured to be larger under the SPM because more people are counted as
having received those payments.55
In previous years, more working-age adults have been classified in poverty in the SPM because
those who work are more likely to have work expenses (including child care expenses). Typically,
these expenses are partially offset by EITC, but only working families receive it. Working
families with children could get ACTC, but they have to have qualifying children.
Slightly more of the aged are below poverty under the SPM than under the official measure
because they are more likely to incur MOOP, which are subtracted from income. While MOOP
can be high for the aged, their effect on poverty rates is mitigated by the fact that homeowners
without a mortgage (such as aged persons who have paid off their mortgages and still live in that
house) have lower housing expenses—and in turn lower poverty thresholds—than do mortgagepaying homeowners and renters.
Further details are given in the Census Bureau’s report, The Supplemental Poverty Measure:
2020.56
54 The 2020 SPM poverty rate would have been 3.6 percentage points higher if the first two rounds of 2020 stimulus
payments had not been included in that measure; these payments did not exist in 2019. Combining stimulus payments
with other types of refundable tax credits, the 2020 SPM poverty rate would have been 5.2 percentage points higher if
these payments were not included in the measure. In contrast, the 2019 SPM poverty rate would have been 2.4
percentage points higher if refundable tax credits were not included (see Fox and Burns (2021), Appendix Table 6).
55 When determining a family’s poverty status, the resources of all family members are summed and compared with the
relevant poverty threshold, given the family’s size and composition. Changing the definition of a family changes the
members counted as belonging to the family, and the family’s total resource amount changes accordingly. Among the
over 14 million persons classified as poor in 2020 under the official measure but not under the SPM, approximately 2
million lived in families that received unemployment insurance payments according to the official definition of family,
but 2.6 million lived in families that received them according to the SPM’s definition of family (author’s computations,
using data from the 2021 CPS ASEC). Among members of cohabiting partner families, the SPM counted
approximately 4.2 million fewer persons in poverty in 2020 compared with the official measure, which treats
cohabiting partners separately (see Fox and Burns (2021), Appendix Table 2). In 2019, the corresponding figure was
2.6 million (see Liana Fox, The Supplemental Poverty Measure: 2019, U.S. Census Bureau, September 2020, Appendix
Table 2, at https://www.census.gov/content/dam/Census/library/publications/2020/demo/p60-272.pdf). The impact on
the SPM of the increase in unemployment insurance payments between 2019 and 2020 can also be seen by
recomputing SPM poverty rates without including these payments. If unemployment insurance payments were not
counted in the SPM, the 2020 SPM poverty rate would have been 1.7 percentage points higher; in contrast, the 2019
SPM poverty rate would have been approximately 0.2 percentage points higher (see Fox and Burns (2021), Appendix
Table 6).
56 Liana E. Fox and Kalee Burns, The Supplemental Poverty Measure: 2020, U.S. Census Bureau, September 2021,
https://www.census.gov/library/publications/2021/demo/p60-275.html.
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Geographic Differences
As shown in Table A-1 in the Appendix, poverty thresholds in the SPM vary geographically and
are typically different from their corresponding official poverty threshold. The SPM thresholds
for New York illustrate within-state variation. SPM thresholds for the Binghamton metro area are
either lower than or within $300 of their corresponding official poverty threshold, while for New
York City they are considerably higher (between $2,500 and $10,000 higher in 2020 than their
corresponding official threshold).
As was discussed earlier, in 2020 SPM poverty rates were lower than those measured under the
official measure for the first time; this also was true in all four regions of the country.
Nevertheless, regional patterns emerged. In previous years, poverty rates in the Northeast and
West tended to be higher under the SPM than under the official measure, in part because of the
relatively higher thresholds in those regions, compared with the Midwest and the South. In 2020,
the SPM poverty rates for the Northeast and the West were lower than their respective official
poverty rates, but by smaller margins (1.6 and 0.4 percentage points, respectively) than in the
Midwest and South (3.5 and 3.1 percentage points, respectively).57
The SPM thresholds in 2020 for California (a western state) and South Carolina (a southern state)
illustrate the most extreme examples: the highest poverty threshold ($46,538 for renters in the
San Jose-Sunnyvale-Santa Clara metro area, California) and the lowest poverty threshold
($21,251 for homeowners without mortgages in small metropolitan areas in South Carolina) were
found to apply in these states (see Table A-1 for additional examples).
As a caveat, while the SPM thresholds lead to higher poverty rates being reflected in the
Northeast and Midwest and lower poverty rates in the South and West compared with the official
measure, the thresholds are not the only driver of SPM poverty rates. Regional differences in
income, noncash benefits, and items subtracted from SPM resources (such as MOOP or work
expenses) also drive differences in regional poverty rates.
Limitations of the SPM and Outstanding Issues
Data Considerations
Because it is based mainly on survey data, the SPM warrants the same caveats as do any
estimates based on surveys (including the official poverty measure): the data are estimates based
on a sample of the population and, as a result, have margins of error. Additionally, means-tested
transfers and certain types of non-transfer income are underreported in the CPS ASEC.58
Portions of SPM resources—notably the values of taxes and some noncash benefits—are not
asked of respondents in the CPS ASEC and need to be estimated using models. The models take
care to use administrative data where appropriate to ensure that the estimated amounts reflect
external totals and distributions; nevertheless, the estimated amounts are not perfect. For
57 Fox and Burns (2021), Appendix Table 2.
58 For a discussion of the underreporting of means-tested transfers, see Laura Wheaton, “Underreporting of Means-
Tested Transfer Programs in the CPS and SIPP,” Urban Institute Research Report, February 6, 2008,
http://www.urban.org/research/publication/underreporting-means-tested-transfer-programs-cps-and-sipp/view/
full_report. For an analysis of income underreporting comparing CPS ASEC income to National Income and Product
Accounts, see Jonathan L. Rothbaum, “Comparing Income Aggregates: How Do the CPS and ACS Match the National
Income and Product Accounts, 2007-2012,” U.S. Census Bureau, SEHSD Working Paper 2015-01, January 14, 2015,
https://www.census.gov/content/dam/Census/library/working-papers/2015/demo/SEHSD-WP2015-01.pdf.
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example, the estimated total benefits from both the EITC and the child tax credit have been found
to be substantially lower than those found when examining federal income tax returns.59 Thus, the
estimates may understate the impact these two tax provisions have on poverty as measured by the
SPM.
Cash Valuation of Noncash Benefits: Not Fully Interchangeable
The SPM includes the values of in-kind food and housing benefits in measuring resources. While
resources such as these are used to meet the needs (FCSU) specified in the thresholds, and thus it
is consistent to include them as resources in the SPM, in-kind benefits, unlike money income, are
not fungible. That is, barring illegal trading, they cannot be used to meet any expense that arises,
but only the needs for which they are specified. While the FCSU amounts in the thresholds are
based empirically on spending patterns, it should not be assumed that every family’s needs are the
same. Because a family could use money income to meet its specific levels of need, but does not
have the same flexibility with in-kind benefits, the in-kind benefits are worth somewhat less than
their face value to families whose needs are met in one area but not another.
In measuring resources, the SPM method caps housing benefits because a large housing subsidy
can only fill housing needs. Housing benefits are capped at the housing portion of the SPM
poverty threshold minus the amount of rent paid by a tenant. On the other hand, under the SPM,
SNAP benefits are counted at their full face value, even though their “value” to the recipient
might be less than that amount.60
Out-of-Pocket Medical Costs Are Measured, But Not the Full Benefit of
Medical Subsidies
The SPM accounts for expenses for health care and insurance by subtracting MOOP from family
resources, but it does not count the value of health insurance as a resource. That is, it subtracts
from resources health insurance premium payments, deductibles, copayments, and other out-ofpocket health expenses made by the family. Medical needs are also not included in the SPM
poverty thresholds.
This treatment of medical expenses does not take account of all the economic effects of
subsidized medical care generally. Two families with different health insurance arrangements, and
different health care needs, but the same amounts of MOOP would be treated identically by the
SPM: their (identical) MOOP would be subtracted from their income. However, those same
families may not be equally as well off if one of the families kept its out-of-pocket costs down by
59 See Laura Wheaton and Kathryn Stevens, The Effect of Different Tax Calculators on the Supplemental Poverty
Measure, Urban Institute, April 2016. For 2012, federal tax returns reported a total of $64.1 billion for the EITC, but
the tax model used by the Census Bureau accounted for only 71% of that total, a shortfall of close to $19 billion. There
was also a shortfall on the estimate of the Additional Child Tax Credit (ACTC), the refundable portion of the child tax
credit, totaling about $11 billion for that year.
60 Research has been undertaken on how capping the values of food subsidies may be implemented in the SPM, but
those caps have not yet been implemented as of the cover date of this report. According to a 2020 research paper, the
caps would have had minimal impacts on SPM estimates for 2018. However, recent expansions to SNAP and other
types of food assistance likely would affect SPM estimates to a greater degree in 2020 and subsequent years than these
programs did in 2018. The authors noted, “expansions to nutritional assistance programs could potentially magnify the
implications of capping, while omitting very real benefits received by individuals.” For details, see Liana E. Fox and
Kalee Burns, “Capping Nutritional Assistance in the Supplemental Poverty Measure,” U.S. Census Bureau, SEHSD
Working Paper #2020-17, September 2020, https://www.census.gov/content/dam/Census/library/working-papers/2020/
demo/SEHSD-WP2020-17.pdf.
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purchasing a less comprehensive insurance plan than the other family and decided to forego
certain types of health care. The SPM thresholds were defined to include the recurring needs of
food, clothing, shelter, utilities, and a little more for miscellaneous expenses; MOOP are
subtracted from family income because they cannot be used to meet the needs identified in the
threshold.
This treatment of medical expenses also means that some of the largest noncash benefits
programs—Medicare, Medicaid, and premium assistance under the Patient Protection and
Affordable Care Act—are not explicitly taken into account in determining SPM poverty status.
There has been some research into methods and measures that would incorporate medical risk,
and how it is affected by health insurance, into measures of economic well-being to complement
the current SPM.61
Lump Sum Nature of Tax Credits
Tax credits, when they are provided to filers, are given as a lump sum based on income in the
previous year. The SPM imputes taxes paid and tax credits in the year they are earned, but
typically the credit would not appear in the family’s income until the following year.62
Furthermore, tax credits are given as a lump sum, but poverty is a spell phenomenon. Both the
SPM and the official poverty measure examine resources in a full calendar year compared with a
threshold based on the calendar year. The economic status of families, however, can change
throughout the year. A family may experience poverty because one or more workers in the family
lost a job and months passed before the worker was able to find another one, putting the family in
a poverty spell for that duration. The tax credit, therefore, may or may not provide relief during
the poverty spell, depending on the spell’s timing in the year and the severity of expenses faced
by the family throughout the year. Longitudinal datasets like the Survey of Income and Program
Participation can unmask the length of time people and families spend in poverty. However, they
typically have smaller sample sizes than the CPS ASEC, which limits their ability to provide
detailed geographic analyses.
Nature of the SPM: a Relative or an Absolute Measure?
There has been some debate about whether the SPM is closer to a relative or an absolute poverty
measure. A relative poverty measure is one in which poverty is defined with respect to some
percentile of the income distribution (e.g., half of median income), while an absolute measure
uses a fixed dollar cutoff updated for inflation over time.
Relative poverty measures keep pace with changes in the income distribution over time and
identify the economically worst-off portion of the population, but they may not necessarily be
tied to a particular level of well-being. Because relative poverty measures are based on the
income distribution, it is possible for poverty rates under a relative measure to increase even
61 For example, see John Creamer, “Incorporating Health Insurance in Poverty Measurement: Implementing a Health
Inclusive Poverty Measure in the United States,” U.S. Census Bureau, Working Paper SEHSD-WP2021-26, December
2021, at https://www.census.gov/library/working-papers/2021/demo/SEHSD-WP2021-26.html, and Michael J.
O’Grady and Gooloo Wunderlich, eds., Medical Care Economic Risk: Measuring Financial Vulnerability from
Spending on Medical Care, National Academies Press, 2012.
62 Part of the Child Tax Credit in 2021 was obtainable in advance (see CRS In Focus IF12025, Refundable Tax Credits
for Families in 2021, by Margot L. Crandall-Hollick). If the tax code were to change to allow tax credits to be
obtainable in advance, then the lump sum nature of tax credits may become less of a limitation of the SPM. For other
considerations of advancing refundable tax credits, see CRS In Focus IF11811, Advancing Refundable Tax Credits:
Policy Considerations, by Margot L. Crandall-Hollick and Conor F. Boyle.
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when incomes throughout the distribution rise if the distribution of income becomes wider. This
potential disconnection between the poverty rate and levels of well-being is considered to be a
weakness of relative measures.
Absolute poverty measures are set to a fixed income amount representing a level of economic
well-being at a point in time, adjusted periodically for inflation. They are consistent over time in
representing the number of people below a resource level, and are more sensitive over time than
relative measures to detecting the shares of the population unable to obtain this level, and
presumably, economic well-being.63
The SPM includes aspects of both relative and absolute measures in its computation, and gauging
whether the SPM is closer to one or the other is an unresolved question. The SPM thresholds are
based on roughly 83% of the median expenditures on FCSU, using five recent years of CE data
(with a one-year lag from the most recent). In this sense, the SPM can be thought of as relative
because the thresholds are computed based on a percentile within the distribution of expenditures.
On the other hand, the thresholds are not computed using overall income, but rather expenditures,
and only for a limited set of basic goods (FCSU, plus 20% extra for miscellaneous expenses). It is
possible for incomes to rise at a different rate than expenditures on basic goods and necessities,
which if true would imply that the SPM is not a relative measure.64 Moreover, expenditures on
63 Absolute poverty measures are predicated on comparing levels of well-being over time, and the assumption that
those levels of well-being are truly consistent. This is difficult to ascertain for two reasons: prices on items purchased
by the poor may rise at a different rate from prices generally, and the types of available goods and services change over
time.
For instance, cell phones were developed in the 20th century, and according to the Pew Research Center, 62% of U.S.
adults owned a cell phone in 2002. By 2016, this percentage had risen to 95% (surveys conducted 2002-2016,
http://www.pewinternet.org/fact-sheet/mobile/, downloaded July 20, 2017). Over the same period, the availability of
pay phones declined, from over 1.7 million in 2002 to 99,832 in 2016 (Federal Communications Commission, Industry
Analysis and Technology Division, Data and Statistical Reports, “Payphone Statistics: 1997-Most Recent,”
https://www.fcc.gov/file/12198/download, downloaded July 20, 2017). Not only do these trends illustrate a new
product offering a level of convenience that was not available before, but also the reduction of a type of infrastructure
that someone with limited resources might have used, in previous years, as a substitute for purchasing their own phone
plan as a way to reduce expenses. This change in the range and cost of available options complicates the comparison of
well-being for low-income persons with regard to telephone service over the past few decades. To compare well-being
over time, additional goods and services should be considered, as well as the degree to which one good or service can
be substituted for another.
Technological change, and its effects on whether goods are considered luxuries or necessities, is not new to the
economics literature. A classic example appears in Chapter II, Part II of Adam Smith, The Wealth of Nations (1776),
regarding the use of linen shirts in the 18th century versus earlier eras.
As a result, some have expressed skepticism as to whether any poverty measure can truly be considered “absolute.” For
example, Smeeding, et al., claim that an absolute poverty measure “conveys an unwarranted objectivity” and that “a
poverty standard cannot be established independently of the economic and social context within which needs arise and
are defined.”; Timothy Smeeding, et al., “Poverty, Inequality, and Family Living Standards Impacts across Seven
Nations: The Effect of Noncash Subsidies for Health, Education, and Housing,” Review of Income and Wealth, vol. 39
no. 3, 1993, pp. 229-256.
For a discussion of how poverty lines had been considered in the 19th and 20th centuries, see Gordon M. Fisher, “Is
There Such a Thing as an Absolute Poverty Line Over Time? Evidence from the United States, Britain, Canada, and
Australia on the Income Elasticity of the Poverty Line,” Joint Newsletter of the Government Statistics Section and the
Social Statistics Section of the American Statistical Association, Summer 1996, pp. 10-12, reproduced on the Census
Bureau’s website at https://www.census.gov/library/working-papers/1995/demo/fisher-01.html.
64 Preliminary evidence examining SPM thresholds and median income over time suggested that it is reasonable to be
skeptical of whether the SPM thresholds are driven primarily by the income distribution, though the evidence that the
researchers had available at the time of their publication was not conclusive. See Daniel Moskowitz, Ron Haskins, and
Timothy Smeeding, “Is the Census Bureau’s supplemental poverty measure a relative measure of poverty?” The
Brookings Institution, Center on Children and Families, May 11, 2010, https://www.brookings.edu/research/is-the-
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FCSU are driven not only by income but also by prices, which can be affected by factors other
than the income distribution.
In order to better ascertain whether the SPM is closer to an absolute or a relative measure, Figure
2 depicts the median SPM threshold (in 2020 dollars) as a percentage of the median SPM
resource amount (also in 2020 dollars). The median is the value that divides the population in two
groups: one with half below the median, and the other half above the median. The medians shown
divide the counts of persons (as opposed to families) into two groups, because the overall poverty
rate is computed using the poverty status of persons.
Because the SPM thresholds are based on expenditures on food, clothing, shelter, and utilities,
then if the SPM were a purely relative measure one would expect the threshold to be a fixed
percentage of resources. In other words, if people’s resource levels were to increase, then their
expenditures on FCSU would be expected to increase proportionally and in turn the thresholds
would increase proportionally. If, on the other hand, the SPM were a purely absolute measure,
one would expect expenditure levels for food, clothing, shelter, and utilities to remain constant,
regardless of people’s resource levels—because those items, as they are computed in the
thresholds, are supposed to reflect basic needs. In other words, if people’s resources increase,
then the additional resources would be expected to go toward other goods and services once the
basic needs had been met. If the SPM were a purely absolute measure, then as resources
increased, one would expect the thresholds as a percentage of resources to decrease (which would
be depicted as a downward-sloping line).
As seen in Figure 2, the median threshold as a percentage of median resources is not completely
flat, nor is it completely downward-sloping, suggesting the SPM is neither completely absolute
nor completely relative. That percentage tends to rise during recessions (the shaded vertical bars),
when income growth stalls or declines, and often falls during expansions, when incomes are
likely to rise.65 These short-term fluctuations suggest the SPM behaves more like a relative
measure in short-term periods, but the overall downward trend suggests it behaves more like an
absolute measure in the long run.
census-bureaus-supplemental-poverty-measure-a-relative-measure-of-poverty/.
65 The historical SPM data were estimated by a team of researchers based at Columbia University. SPM data produced
by the Census Bureau are only available for 2009 onward. The Columbia University researchers attempted to apply the
SPM methodology to previous years’ data, computing estimates for the SPM components that were unavailable in
previous years, taxes and refundable tax credits for SPM-defined families specifically, the value of in-kind benefits like
SNAP (or food stamps, as food assistance was previously called), work-related expenses, and so on. The data series
produced by the Columbia University researchers ended at 2015. For details on the dataset and links to its underlying
research, see https://www.povertycenter.columbia.edu/historical-spm-data. For a comparison of official poverty rates
(which use cash income only) with respect to recessions over time, see CRS Report R45854, Trends in the U.S. Poverty
Rate after Recessions, by Joseph Dalaker. In recent recessions, the official poverty rate has taken multiple years after a
recession’s end to register statistically significant year-to-year declines.
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Figure 2. Median SPM Threshold As a Percentage of Median SPM Resources
Historical SPM data through 2014 estimated by the Center on Poverty and Social Policy at Columbia
University, Columbia Population Research Center, 2017; data for 2015-2020 from U.S. Census Bureau.
Source: Congressional Research Service analysis of historical SPM dataset (Jane Waldfogel, Chris Wimer, Liana
Fox, Irwin Garfinkel, Neeraj Kaushal, Jennifer Laird, Jaehyun Nam, Laura Nolan, and Jessica Pac, Historical
Supplemental Poverty Measure Data, Columbia Population Research Center, 2017,
https://www.povertycenter.columbia.edu/). Data for 2015-2020 from U.S. Census Bureau, Current Population
Survey, 2016-2021 Annual Social and Economic Supplements. SPM variables for 2015-2017 obtained from
https://www.census.gov/topics/income-poverty/supplemental-poverty-measure/data/datasets.html.
The metric used in Figure 2 (tracking the median threshold as a percentage of median resources
over time) has some complicating factors. Long-term trends in family size, homeownership,
migration within different parts of the country, and housing costs (both nationally and in how
local areas’ housing costs compare with one another) all affect either the SPM thresholds,
resources, or both. It is an open question as to whether a poverty measure is supposed to consider
the effects of these trends as intrinsic to determining what is a constant level of a person’s or
family’s well-being, or if the poverty measure is supposed to remain independent from such
trends. However, acknowledging that these trends exist helps to highlight how complicated it is to
decide which factors are relevant for measuring poverty:
If a poverty measure is supposed to hold constant a particular level of well-being,
then what is the appropriate way to find what that constant level of well-being is,
when the choices available to individuals and families—in where to live and how
much it costs to rent or buy a home; in the relative cost advantages or
disadvantages of forming families, living with adult relatives, living with
nonrelatives, or living on one’s own; and in the availability of work and child
care options—all change over time and vary from place to place?
Alternatively, if the level of well-being defined in a poverty measure ought to be
derived distinctly from the choices of goods and services that are available to
families and individuals in any one year, then what would such a poverty
measure imply for families and individuals faced with a different set of economic
choices now than in previous years? For example, if air conditioning is now
commonly a standard feature in rental units but was not a common feature in
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
previous years, does that make families who rent unequivocally better off now
compared with before, if they no longer have the option of choosing housing
without air conditioning for a lower cost of rent?
More generally, should a poverty measure reflect that higher costs of goods and
services sometimes reflect higher levels of quality, services, or amenities, and
sometimes do not? This question can affect both absolute measures (by
comparing cost and quality over time) and relative measures (by comparing cost
and quality in different areas at the same time).
The question of whether the SPM is relative or absolute has meaning for those trying to evaluate
whether the SPM accurately describes the poor population both in a single year and over time.66 It
also highlights the value judgments involved in determining what is meant by poverty and in
expressing that determination using a concrete metric.67 In the case of the official poverty
measure, the level of well-being was originally characterized by the likely nutritional impact of
the Economy Food Plan, with fewer than 1 in 10 families on that plan in the 1960s meeting their
recommended nutritional requirements, and about half of families on that plan failing to get twothirds of them (see footnote 34). The description of the SPM in this report, and the tables
provided in the Appendix, are intended to help readers better gauge for themselves the levels of
well-being on which the SPM is based.
66 In addition to the demographic analysis of who is poor under the official measure and under the SPM, such as that
presented in Census Bureau reports and in the “Insights Obtainable from the SPM” section of this report, others have
compared the SPM’s poor population with consumption-based measures—that is, taking account of spending, which
may be based on access to credit or using up savings, and not solely on income. For example, see Bruce Meyer and
James X. Sullivan, “Identifying the Disadvantaged: Official Poverty, Consumption Poverty, and the New Supplemental
Poverty Measure,” Journal of Economic Perspectives, vol. 26 no. 3, Summer 2012, pp. 111-136. Meyer and Sullivan
conclude that in comparison with the official measure, the SPM “adds to poverty individuals who have higher
consumption levels and are more likely to be college graduates; to own a home and a car; to live in a larger housing
unit; and to have other more favorable characteristics than those who are dropped from poverty.”
In a different study of material hardship (John Iceland and Kurt Bauman, “Income Poverty and Material Hardship: How
Strong is the Association?” National Poverty Center Working Paper No. 04-17, December 2004), using longitudinal
data, Iceland and Bauman noted differences in material hardship between the long-term poor and the temporarily poor,
with the long-term poor possessing fewer amenities.
67 While the NAS panel, whose writing laid the groundwork for the SPM, noted that “the panel has taken great care to
make clear at each step ... the character and status of the scientific evidence and the role of judgment” (Constance F.
Citro and Robert T. Michael, eds., Measuring Poverty: A New Approach, Panel on Poverty and Family Assistance:
Concepts, Information Needs, and Measurement Methods, Committee on National Statistics, National Research
Council, 1995, Preface, p. xvii, http://www.nap.edu/catalog/4759/measuring-poverty-a-new-approach), one member,
Dr. John Cogan, dissented from the panel’s approach. Cogan argued that the panel’s recommendations “are not
scientific judgments. They are value judgments made by scientists—with a particular point of view. In essence, the
panel has mostly eschewed the role of scientific panel and has instead assumed the role of a government policy maker,”
(Measuring Poverty, Appendix A, p. 386).
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The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Appendix. Poverty Thresholds under the SPM and
the Official Poverty Measure
Unlike the official poverty measure, which uses 48 poverty thresholds that are updated annually
for inflation and applied nationwide, the SPM thresholds are computed using additional variables,
resulting in thousands of thresholds once they are geographically adjusted. The SPM thresholds
are based on Consumer Expenditure Survey (CE) data for food, clothing, shelter, and utilities
(FCSU), and adjustments are made thereafter by housing tenure (that is, for homeowners with
mortgages, homeowners without mortgages, and renters), by geographic variations in housing
costs for each housing tenure group, and by family composition.68
Three tables are shown below, to illustrate the dollar amounts used to determine poverty status in
both the SPM and the official measure. Table A-1 focuses only on SPM poverty thresholds for a
two-adult two-child family, by housing tenure, and illustrates the range of geographic cost
variation. In contrast, Table A-2 illustrates how the SPM thresholds vary by family composition,
but without geographic adjustment. Table A-3 presents the official poverty thresholds, for
comparison.
Table A-1. Supplemental Poverty Measure (SPM) Thresholds in 2020 for a TwoChild, Two-Adult Family in Selected Metropolitan and Nonmetropolitan Areas
Amounts in 2020 dollars. Thresholds do not include estimated values for noncash benefits. The
corresponding official poverty threshold in 2020 was $26,246.
Homeowners
With a Mortgage
Homeowners
Without a
Mortgage
Renters
$29,959
$25,222
$30,150
South Carolina, small metro areas aggregated
23,763
21,251
23,872
South Carolina, nonmetro
25,424
22,315
25,555
Charleston-North Charleston, SC MSA
30,763
25,737
30,965
Columbia, SC MSA
28,166
24,073
28,334
New York, nonmetro
26,374
22,924
26,517
Albany-Schenectady-Troy, NY MSA
30,447
25,535
30,644
Thresholds before geographic adjustmenta
South (South Carolina)
Northeast (New York)
68 “Family” here is used loosely. The more accurate term is “consumer unit” for the initial computations performed by
the Bureau of Labor Statistics, leading up to reference thresholds by tenure group for consumer units with two adults
and two children, since these computations are performed using the CE and the consumer unit concept is used in the
CE. “SPM resource unit” is used for the remaining computations, resulting in the SPM thresholds; these remaining
steps involve demographic survey data and are performed by the Census Bureau. Both of these terms differ from the
Census Bureau’s definition of a family: for details see the section “Family Units in the SPM.”
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Homeowners
With a Mortgage
Homeowners
Without a
Mortgage
Renters
Binghamton, NY MSA
26,756
23,169
26,904
New York-Newark-Jersey City, NY-NJ-PA MSA
35,548
28,805
35,813
Wisconsin, nonmetro
26,163
22,789
26,303
Oshkosh-Neenah, WI MSA
26,888
23,253
27,038
Madison, WI MSA
30,368
25,484
30,564
Milwaukee-Waukesha-West Allis, WI MSA
28,549
24,318
28,721
California, nonmetro
29,643
25,019
29,829
Bakersfield, CA MSA
28,259
24,132
28,427
Los Angeles-Long Beach-Anaheim, CA MSA
37,657
30,156
37,950
San Jose-Sunnyvale-Santa Clara, CA MSAb
46,133
35,589
46,538
Midwest (Wisconsin)
West (California)
Source: Congressional Research Service, excerpted from U.S. Census Bureau, “SPM Thresholds by Metro Area:
2020,” https://www2.census.gov/programs-surveys/demo/tables/p60/275/pov-threshold-2020.xlsx.
Thresholds without geographic adjustment computed by Juan D. Munoz, and under the guidance of Thesia I.
Garner, Division of Price and Index Number Research, Bureau of Labor Statistics (BLS), using the U.S. Consumer
Expenditure Interview Survey. The thresholds are not BLS production quality. The work is solely that of the BLS
authors and does not necessarily reflect the official positions or policies of the Bureau of Labor Statistics, or the
views of other BLS staff members. See https://www.bls.gov/pir/spm/spm_threshold_200520.xlsx.
Threshold geographic adjustments computed by U.S. Census Bureau using housing data from American
Community Survey 5-Year Estimates, 2014- 2018.
Notes: MSA = Metropolitan Statistical Area.
a. Only the thresholds for a four-person family, with two adults and two children, are shown here. The full
complement of thresholds varies by family size, ages of the members, and whether the adult is a single parent, as
well as by housing status (as shown in the three columns here). See Table A-2.
b. Among all geographic areas computed, the aggregate of small metropolitan areas in South Carolina had the
lowest threshold, and the Metropolitan Statistical Area (MSA) of San Jose-Sunnyvale-Santa Clara, CA, had the
highest. The geographic areas in this table were selected to illustrate the range of dollar amounts used as SPM
thresholds and to provide examples using one state from each of the four Census regions of the country:
Northeast (New York), Midwest (Wisconsin), South (South Carolina), and West (California).
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Table A-2. Supplemental Poverty Measure (SPM) Thresholds by Housing Status, Number of Adults, and Number of Children
under 18 Years, Without Geographic Adjustment: 2020
Thresholds in 2020 dollars. Selected thresholds presented for SPM resource units (families) of eight members or fewer. Additional thresholds may be
computed for families of larger sizes. The total number of family members (adults and children) is listed vertically, as are headings for housing status and
single-parent status; the number of members that are children is shown in columns.
Size of Family Unit
Number of Children under 18 Years
0 (adults
only)
1
2
3
4
5
6
7
8
…
$41,630
$44,621
…
Homeowners With a Mortgage
One person (unrelated
individual)
$13,885
Two people
$19,578
$20,952
Three people
$29,959
$26,369
Four people
$36,642
$33,373
$29,959
Five people
$42,837
$39,792
$36,642
$33,373
Six people
$48,669
$45,793
$42,837
$39,792
$36,642
Seven people
$54,214
$51,473
$48,669
$45,793
$42,837
$39,792
Eight people
$59,526
$56,896
$54,214
$51,473
$48,669
$45,793
$42,837
NA
$20,952
$24,874
$28,547
$32,026
$35,350
$38,545
Two or more adults
…
One adult with child/children
Single parent
Homeowners Without a Mortgage
One person (unrelated
individual)
CRS-32
$11,689
Size of Family Unit
Number of Children under 18 Years
0 (adults
only)
Two people
1
2
3
4
5
6
$16,482
$17,639
Three people
$25,222
$22,200
Four people
$30,849
$28,096
$25,222
Five people
$36,064
$33,500
$30,849
$28,096
Six people
$40,973
$38,552
$36,064
$33,500
$30,849
Seven people
$45,642
$43,335
$40,973
$38,552
$36,064
$33,500
Eight people
$50,114
$47,900
$45,642
$43,335
$40,973
$38,552
$36,064
NA
$17,639
$20,941
$24,033
$26,962
$29,761
$32,451
7
8
…
$35,048
$37,565
…
Two or more adults
…
One adult with child/children
Single parent
Renters
One person (unrelated
individual)
$13,973
Two people
$19,703
$21,086
Three people
$30,150
$26,538
Four people
$36,876
$33,585
$30,150
Five people
$43,110
$40,045
$36,876
$33,585
Six people
$48,979
$46,085
$43,110
$40,045
$36,876
Seven people
$54,560
$51,801
$48,979
$46,085
$43,110
$40,045
Eight people
$59,905
$57,259
$54,560
$51,801
$48,979
$46,085
Two or more adults
CRS-33
$43,110
Size of Family Unit
Number of Children under 18 Years
0 (adults
only)
1
2
3
4
5
6
7
8
…
$21,086
$25,033
$28,729
$32,230
$35,575
$38,791
$41,896
$44,905
…
…
One adult with child/children
Single parent
NA
Source: Congressional Research Service, based on U.S. Census Bureau, “SPM Thresholds by Metro Area: 2020,” https://www2.census.gov/programs-surveys/demo/
tables/p60/275/pov-threshold-2020.xlsx.
Two-adult two-child reference thresholds without geographic adjustment computed by Juan D. Munoz, under the guidance of Thesia I. Garner, Division of Price and
Index Number Research, Bureau of Labor Statistics (BLS), using the U.S. Consumer Expenditure Interview Survey. Scaling by the number of adults and children
performed by the U.S. Census Bureau.
Notes: The two-adult two-child reference thresholds are not BLS production quality. The work is solely that of the BLS authors and does not necessarily reflect the
official positions or policies of the Bureau of Labor Statistics, or the views of other BLS staff members. See https://www.bls.gov/pir/spm/spm_chart2_2020data.htm.
NA: Not applicable.
Ellipses ( ... ) indicate that thresholds for additional members are possible to compute but are not displayed. The thresholds above use a geographic housing cost index
equal to 1.000 (that is, housing costs without any geographic cost adjustment).
CRS-34
Table A-3. Official Poverty Thresholds for 2020 by Family Size and Number of Related Children Under 18 Years
Thresholds in 2020 dollars. The total number of family members (adults and children), and the age of the householder, where applicable, are listed vertically;
the number of family members that are children is shown in columns.
Size of Family Unit
Related Children under 18 Years
0
1
2
3
4
5
6
7
8 or More
One person (unrelated individual):
Under age 65
$13,465
Aged 65 and older
$12,413
Two people:
Householder under age 65
$17,331
$17,839
Householder aged 65 and older
$15,644
$17,771
Three people
$20,244
$20,832
$20,852
Four people
$26,695
$27,131
$26,246
$26,338
Five people
$32,193
$32,661
$31,661
$30,887
$30,414
Six people
$37,027
$37,174
$36,408
$35,674
$34,582
$33,935
Seven people
$42,605
$42,871
$41,954
$41,314
$40,124
$38,734
$37,210
Eight people
$47,650
$48,071
$47,205
$46,447
$45,371
$44,006
$42,585
$42,224
Nine people or more
$57,319
$57,597
$56,831
$56,188
$55,132
$53,679
$52,366
$52,040
$50,035
Source: Congressional Research Service adaptation of table from U.S. Census Bureau, https://www2.census.gov/programs-surveys/cps/tables/time-series/historicalpoverty-thresholds/thresh20.xls.
CRS-35
The Supplemental Poverty Measure: Its Core Concepts, Development, and Use
Author Information
Joseph Dalaker
Analyst in Social Policy
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
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under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
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Congressional Research Service
R45031 · VERSION 4 · UPDATED
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