Opinion

IN THE UNITED STATES DISTRICT COURT FOR THE

WESTERN DISTRICT OF MISSOURI

WESTERN DIVISION

TINA RICHARDSON, individually and as )

successor-in-interest to Decedent Caleb Slay, )

)

Plaintiff, )

)

v. ) Case No. 6:23-cv-03337-RK

)

UNITES STATES OF AMERICA, et al., )

)

Defendants. )

ORDER

Before the Court are Defendant United States’ motion to exclude the expert testimony of

Robert Johnson, (Doc. 138),1 and Plaintiff Richardson’s motion to exclude the expert testimony of

Craig Allen, (Doc. 139). The motions are fully briefed. (Docs. 138, 139, 156, 157, 161, 162.)

After careful consideration and for the reasons explained below, the Court ORDERS that

(1) Defendant United States’ motion to exclude the expert testimony of Robert Johnson is

GRANTED, and (2) Plaintiff Richardson’s motion to exclude the expert testimony of Craig Allen

is DENIED.

Background

This case arises from the fatal shooting of Caleb Slay by federal Drug Enforcement

Administration (“DEA”) Agent Anthony Gasperoni. On November 2, 2020, Slay encountered

DEA Agent Gasperoni and DEA Agent John Stuart. During the ensuing interaction, DEA Agent

Gasperoni discharged his firearm, fatally shooting Slay. Slay’s mother, Tina Richardson, filed this

case asserting numerous claims under federal and state law against the United States and DEA

Agent Gasperoni for excessive force, wrongful death, and battery. Following summary judgment,

the sole remaining claim in this case is a wrongful death claim brought against the United States

pursuant to the Federal Tort Claims Act and Missouri’s wrongful death statute, based on a battery

1 The motion by Defendant United States was originally filed jointly with former co-defendant

DEA Agent Gasperoni to exclude Plaintiff Richardson’s expert testimony of Robert Johnson. Since the

filing of the motion to exclude however, the Court granted co-defendant DEA Agent Gasperoni’s motion

for summary judgment in full and granted in part the United States’ motion for summary judgment, leaving

the United States as the sole remaining defendant in this case.

theory (Count 5). (See Doc. 163.) The parties timely designated expert witnesses in this case and

now move to exclude the evidence and testimony of the other party’s expert.

Legal Standard

Rule 702 of the Federal Rules of Civil Procedure, which was amended following Daubert

v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), and most recently amended in 2023,

provides the standard for the admission of expert testimony:

A witness who is qualified as an expert by knowledge, skill, experience, training,

or education may testify in the form of an opinion or otherwise if the proponent

demonstrates to the court that it is more likely than not that: (a) the expert’s

scientific, technical, or other specialized knowledge will help the trier of fact to

understand the evidence or to determine a fact in issue; (b) the testimony is based

on sufficient facts or data; (c) the testimony is the product of reliable principles and

methods; and (d) the expert’s opinion reflects a reliable application of the principles

and methods to the facts of the case.

Fed. R. Evid. 702. Based on Rule 702, the Eighth Circuit applies a three-part test to determine the

admissibility of expert testimony:

First, evidence based on scientific, technical, or other specialized knowledge must

be useful to the finder of fact in deciding the ultimate issue of fact. This is the basic

rule of relevancy. Second, the proposed witness must be qualified to assist the

finder of fact. Third, the proposed evidence must be reliable or trustworthy in an

evidentiary sense, so that, if the finder of fact accepts it as true, it provides the

assistance the finder of fact requires.

Lauzon v. Senco Prods., Inc., 270 F.3d 681, 686 (8th Cir. 2001) (internal quotation marks omitted).2

“The proponent of the expert testimony bears the burden to prove its admissibility.” Menz v. New

Holland N. Am., Inc., 507 F.3d 1107, 1114 (8th Cir. 2007) (citing Lauzon, 270 F.3d at 686).

Following the 2023 amendment, the proponent must show “that it is more likely than not that the

proffered testimony meets the admissibility requirements” of Rule 702. Advisory Committee notes

to 2023 amendment; see also CIS Comm’cns, LLC v. Republic Servs., Inc., No. 4:21-cv-00359-

2 The Eighth Circuit has not directly addressed whether its three-part test from Lauzon still applies

after the 2023 amendment to Rule 702. In Academy Bank, N.A. v. AmGuard Insurance Co., the Eighth

Circuit applied the former Rule 702 standard in a case which was tried prior to the amendment and noted

we “do not decide whether our holding here would be the same if the amendments had been in effect at

trial.” 116 F.4th 768, 790 n.10 (8th Cir. 2024).

However, multiple district courts in the Eighth Circuit have continued to apply the three-part test

from Lauzon after the 2023 amendment to Rule 703. See, e.g., Golden v. United States, No. 22-cv-3312-

WBG, 2024 WL 1743766, at *2 (W.D. Mo. Apr. 23, 2024); Christensen v. Louisville Ladder, Inc., No. 4:23-

cv-136 HEA, 2025 WL 2591619, at *2 (E.D. Mo. Sept. 5, 2025).

JAR, 2025 WL 2958462, at *3 (E.D. Mo. Sept. 26, 2025). The rules for the admissibility of expert

testimony favor admission over exclusion. See Moore v. Wilson Logistics, Inc., No. 21-03212-CV-

S-BP, 2025 WL 1783770, at *2 (W.D. Mo. Feb. 6, 2025) (noting that Rule 702 “is not a rule of

exclusion” and that “cases are legion that, correctly under Daubert, call for the liberal admission

of expert testimony” (quotation modified)); Lauzon, 270 F.3d at 686.

Discussion

I. Defendant United States’ Motion to Exclude Expert Testimony of Robert Johnson

Defendant United States moves to exclude the testimony and report of Plaintiff

Richardson’s damages expert, Robert Johnson. Specifically, the United States argues that Mr.

Johnson’s expert testimony opining that the value of decedent Caleb Slay’s life is between

$5,5000,000 and $16,900,000, based on a “willingness-to-pay” methodology, is not relevant to the

factfinder because the willingness-to-pay valuation is not tied to Mr. Slay specifically in any way.

The United States argues that Mr. Johnson’s opinion is unreliable and that courts have generally

excluded expert testimony which relies on the “willingness-to-pay” methodology or so-called

hedonic damages.3 Plaintiff counters that “Mr. Johnson has sufficient experience in forensic

economics and is qualified to opine on the loss of the value of human life, or Plaintiff’s hedonic

damages” and that this Court should follow the Tenth and Ninth Circuit case law on the issue. The

Court agrees with the United States.

Mr. Johnson, a forensic economist, opines that the value of decedent Caleb Slay’s life is

between $5,500,000 and $16,900,000, based on a “willingness-to-pay” methodology. (Doc. 138-

1 at 3, 5.) As Mr. Johnson explains in his expert report, the willingness-to-pay methodology values

human life based on “how much people are willing to pay (or willing to give up in dollars) to avoid

an increase in the risk of death,” rather than taking into account any information specific to the

decedent (such as physical health, history of mental illness, drug use, familial relationships,

education, etc.).

3 “Hedonic damages” refer to damages that encompass the “lost pleasure of life.” See Maracdo v.

Ahmed, 756 F. Supp. 1097, 1102 (N.D. Ill. 1991). The willingness-to-pay methodology is one of the most

well-known hedonic damages models. While these concepts are thus distinct, courts addressing the issue

of whether willingness-to-pay testimony is admissible often refer to both “hedonic damages” and the

“willingness-to-pay” methodology in the decision to describe the type of expert evidence offered by Mr.

Johnson here.

Mr. Johnson’s report begins with a short example of the willingness-to-pay methodology

in action. The premise of the example is that there is a toxin in a town of 20,000 people which

causes a fatality rate of 3/20,000. The toxin can be reduced so that the fatality rate decreases to

1/20,000, saving two lives:

The townspeople are asked, “How much are they willing to pay to save these two

lives?” It is important to note that the townspeople recognize there is no way of

knowing in advance whose lives are going to be saved. It could be the local vagrant

bum, an infant, spouse, or the local version of Dr. Jonas Salk. All that remains is

the intangible human value of life. Although there was some variation, the average

amount each citizen was willing to pay was $200. Consequently, since the average

citizen was willing to pay $200 for this reduction in the rate of death, then the total

Willingness-to-Pay would be $4,000,000 and the intangible human value of life per

person saved was $2,000,000.

(Doc. 138-1 at 6 (emphasis added).) Mr. Johnson’s own example demonstrates the generality of

this methodology. In other words, the willingness-to-pay model provides a value range for some

general, average human life, rather than a value specific to a particular decedent.

Other courts have found this generality to be a weak point of the willingness-to-pay

methodology, which negates the relevancy of the testimony. See Sullivan v. City of Buena Park,

No. 20-01732-CJC(ADSx), 2022 WL 2965664, at *7 (C.D. Cal. Apr. 11, 2022) (“Most importantly,

however, Mr. Johnson’s testimony will not be helpful to the jury because the range is not tied to

Sullivan in any way (his health, history, relationships, education, career, and suicidal ideation).”);

Estate of DuBose v. City of San Diego, No. 99-cv-2279-L(NLS), 2002 WL 34408963, at *2 (S.D.

Cal. Oct.1, 2002) (“Second, Johnson’s proposed testimony will not assist the jury reach a decision.

The value of DuBose’s life depends on his particular facts (including health, history, relationships,

career, etc.), but this expert gives a range spanning six million dollars that purportedly applies to

‘all’ individuals.”); Smith v. Jenkins, 732 F.3d 51, 67 (1st Cir. 2013) (“But even assuming that Dr.

Smith’s formula is a reliable measure of the value of life, it was of no assistance to the jury in

calculating Smith’s loss of enjoyment of life. As other courts have recognized, ‘[t]he willingness-

to-pay studies do not relate in any way to the actual component of damages, the enjoyment of

life.’” (citation omitted)).4

4 Plaintiff’s expert, Robert Johnson, appears to be the expert in both the Sullivan and Estate of

DuBose cases where the expert testimony was excluded.

Federal courts have overwhelmingly discredited the willingness-to-pay model as a whole,

and thus excluded expert testimony relying on the model, finding that “placing a dollar amount on

hedonic damages, including the use of benchmarks and range of values, does not meet the

reliability and relevance factors required to admit expert testimony.” Rivera v. Volvo Cars of N.

Am., LLC, No. 13-397 KG/KBM, 2015 WL 11118067, at *1 (D.N.M. June 8, 2015).5 This includes

district courts within the Eighth Circuit. See Jennings v. Nash, No. 18-cv-3261-WJE, 2020 WL

770325, at *3 (W.D. Mo. Feb. 17, 2020) (excluding testimony estimating hedonic damages using

a willingness-to-pay model because plaintiff “failed to show how” the testimony “would be

necessary or reliable under the standard set forth in Daubert”); Moe v. Grinnell Coll., 547 F. Supp.

3d 841, 848 (S.D. Iowa 2021) (same).

While the Eighth Circuit has not addressed this issue, multiple courts of appeals have held

the willingness-to-pay model inadmissible or affirmed district courts that excluded such evidence.

See Smith v. Jenkins, 732 F.3d 51, 65-67 (1st Cir. 2013) (rejecting willingness-to-pay methodology

as irrelevant and unreliable); Mercado v. Ahmed, 974 F.2d 863, 871 (7th Cir. 1992) (affirming

district court’s exclusion of willingness-to-pay expert testimony). Plaintiff urges this Court to

follow the Tenth and Ninth Circuits, citing Smith v. Ingersoll-Rand Co., 214 F.3d 1235 (10th Cir.

2000), and Dorn v. Burlington N. Sante Fe R.R., 397 F.3d 1183 (9th Cir. 2005). However, upon

closer review of these cases, they do not support Plaintiff’s contention that the willingness-to-pay

methodology is sufficiently reliable to satisfy a Daubert analysis.

In Smith v. Ingersoll-Rand Co., the Tenth Circuit addressed the defendant’s appeal of the

district court’s ruling admitting expert testimony “about the meaning of hedonic damages.” 214

F.3d at 1244. The Tenth Circuit affirmed the district court decision permitting testimony about the

meaning of hedonic damages, but noted that “[t]his case . . . does not require us to determine the

admissibility of studies purporting to quantify hedonic damages, and we venture no opinion on

that count.” Id. at 1245 (emphasis added). This is because the district court below actually

excluded the expert testimony on hedonic damages to the extent the testimony calculated a value-

range using the willingness-to-pay model because such valuations are “unreliable” and the district

court “concluded any attempt to quantify [plaintiff] Ron Smith’s hedonic damages would be ‘both

5 See also, e.g., Kurncz v. Honda N. Am., 166 F.R.D. 386 (W.D. Mich. 1996); Ayers v. Robinson,

887 F. Supp. 1049 (N.D. Ill. 1995); Hein v. Merck & Co., 868 F. Supp. 230 (M.D. Tenn. 1994); Lopez v.

Aitken, No. 07-cv-2028 JLS (WMC), 2011 WL 672798 (S.D. Cal. Feb. 18, 2011); Saia v. Sears Roebuck &

Co., Inc., 47 F. Supp. 2d 141 (D. Mass. 1999).

unhelpful and confusing to the jury.’” Id. at 1244 (citation omitted). Thus, the Tenth Circuit did

not address the admissibility of expert testimony quantifying the value of human life based on a

willingness-to-pay methodology. The court did, however, note that “[a]ttempts to quantify the

value of human life have met considerable criticism in the literature of economics as well as in the

federal court system” and that “the federal courts which have considered expert testimony on

hedonic damages in the wake of Daubert have unanimously held quantifications of such damages

inadmissible.” Id. at 1245 (collecting cases).

Similarly, in Dorn v. Burlington N. Sante Fe R.R., the Ninth Circuit addressed the

defendant’s appeal of the district court’s admission of the plaintiff’s hedonic damages expert and

exclusion of defendant’s rebuttal expert. The Ninth Circuit concluded in that case that “we need

not reach a conclusion on whether the district court abused its discretion in admitting Smith’s [the

plaintiff’s hedonic damages expert] testimony” because the district court erred by not admitting

the defendant’s rebuttal expert on the issue. Dorn, 397 F.3d at 1195. Therefore, the Ninth Circuit

did not reach the issue of the admissibility of expert testimony using the willingness-to-pay

methodology in its decision, either.6 Thus, the only cases Plaintiff cites in support of the relevance

and reliability of the willingness-to-pay methodology did not actually decide the issue. The United

States, on the other hand, has provided a plethora of case law excluding testimony based on the

willingness-to-pay methodology. The Court is persuaded by the reasoning of those courts that

have rejected similar expert testimony and concludes that the willingness-to-pay methodology is

irrelevant and unreliable generally.

In addition to finding the willingness-to-pay methodology generally unreliable, the Court

notes that Mr. Johnson’s report in particular has issues which cause his expert testimony to fall

short of the Daubert standard. In his report, after describing the “toxin in the town” example

discussed above, Mr. Johnson sets forth his own analysis:

Among the many published studies, two prominent analyses on the Human Value

of Life are (1) “The Plausible Range for the Value of Life”, by Dr. T. Miller and

(2) “The Value of Life: Estimates with Risks by Occupation and Industry”, by Dr.

W. Kip Viscusi. In the Miller study, which represents his critical analysis of over

66 different analyses (by other economists) of the Human Value of Life, he deemed

6 Additionally, the underlying expert opinion in Dorn was based on a “risk-reduction model” versus

a “willingness-to-pay” model, both of which calculate hedonic damages. The Ninth Circuit stated that

“[t]his methodology may have some utility” but that the usefulness of the testimony “was reduced” because

the expert averaged different values, some of which were “not at all informative about how much people

value their own enjoyment of life.” Dorn, 397 F.3d at 1195.

47 as sound. These 47 qualifying studies yielded a statistical floor value of

$2,200,000 (in 1988 dollars). In the Viscusi study, the authors’ empirical analysis

of Bureau of Labor Statistics data yielded a value of life of $8,900,000 (in 1997

dollars).

Thus, after deducting for the Human Capital component and converting to before

tax dollars, the appropriate range for the intangible Human Value of Life is from a

low of $1,800,000 in 1988 dollars to a mid-point of $8,900,000, in 1997 dollars.

When converted (using the Consumer Price Index) into 2023 dollars, the range is

from $5,500,000 to $16,900,000.

(Doc. 183-1 at 6.) The Court includes Mr. Johnson’s analysis in full to demonstrate the

insufficiencies of his report. What is included above is more or less the entirety of Mr. Johnson’s

explanation as to how he arrived at his range for the valuation of Mr. Slay’s life. In Sullivan v.

City of Buena Park, discussed above, the Central District of California excluded a nearly identical

expert report submitted by Mr. Johnson. The Sullivan Court noted that:

Mr. Johnson has provided no explanation as to why he chose the studies that he

chose: those of Miller and Viscusi. For all the Court knows, there could be various

studies out there that may yield a range below that given by Mr. Johnson. The

Miller and Viscusi studies are also quite old. As society, technology, and medicine

change through time, would not the value of life change as well? If there are more

recent studies, Mr. Johnson has not explained why these older studies were more

appropriate to use. And if there are not recent studies, that raises a concern that the

WPT methodology has not been further developed and refined over time, but

perhaps left in the past as junk science.

More troubling, the variability in the values derived from the Miller and Viscusi

studies, and the possible variability between those studies and other studies that Mr.

Johnson decided not to use for some unknown reason, suggests the WPT method’s

unreliability. It does not inspire confidence when a single method meant to value a

generic life could arrive at values millions of dollars apart.

2022 WL 2965664, at *6 (internal citation omitted). This Court finds the same issues in the report

Mr. Johnson prepared in this case. He relies on two studies that are both now over 20 years old.7

Mr. Johnson does not explain why these studies were chosen, whether newer studies exist, or

whether other studies exist with further variations in estimates of the value of human life. Mr.

Johnson’s report in this case is nearly identical to the one he submitted in Sullivan, except that he

converts the final valuation of human life into 2023 dollars rather than 2019 dollars. (Compare

Doc. 183-1, with Doc. 183-4.) Mr. Johnson has not done any further work to update his

7 The Miller study was published in 1990, and the Viscusi study was published in 2004. (Doc.

138-1 at 7.)

methodology in the ensuing years between Sullivan and this case, despite a court excluding his

expert testimony and detailing the insufficiencies in the report; the same insufficiencies thus

remain here.

Ultimately, the Court joins the growing consensus among federal courts and concludes that

the willingness-to-pay methodology generally is an unreliable way to measure the value of human

life and does not satisfy the Daubert standard. Moreover, Mr. Johnson’s report in particular lacks

sufficient explanation and support for his conclusions. The reasonable value of Mr. Slay’s life is

within the purview and experience of the factfinder. See Sullivan, 2022 WL 2965664, at *7 (“The

jury has the knowledge and life experience to value human life and can do something the WPT

methodology cannot: consider the specific facts of Sullivan’s life.”); Estate of Dubose, 2002 WL

34408963, at *2 (“[T]he jury will have the knowledge and life experience to determine a fair

damages award based upon the testimony received at trial. . . . As in any other wrongful death case,

this factual determination is most appropriately left to the province of the jury.”). Plaintiff may

argue whatever valuation she wishes, but the Court finds that Mr. Johnson’s expert testimony does

not meet the standard under Rule 702 as amended and is inadmissible. Therefore, Defendant

United States’ motion to exclude the expert testimony of Robert Johnson is GRANTED.

II. Plaintiff Richardson’s Motion to Exclude Expert Testimony of Craig Allen

Plaintiff moves for an order “excluding, or in the alternative limiting, the testimony of

[Defendant United States’] Expert, Craig Allen, as it relates to ‘Force Science’ and eyewitness

testimony.” (Doc. 139 at 1.)

A. “Force Science” Opinions

Plaintiff Richardson seeks to exclude Mr. Allen’s opinions that rely on “force science,”

arguing that opinions based on so-called force science do not satisfy the Daubert standard because

“force science” is not a generally accepted theory in the relevant scientific community and Mr.

Allen is not qualified as an expert in a recognized scientific field such as cognitive psychology or

behavioral science. (Doc. 139 at 3.) Plaintiff alternatively argues that Mr. Allen’s “force science”

opinions should be excluded under Rule 403 of the Federal Rules of Civil Procedure because any

probative value is outweighed by the danger of unfair prejudice. (Id. at 4.)

To start, the Court notes that Plaintiff does not specify what portion(s) of or opinion(s)

within Mr. Allen’s expert report should be excluded as relying on “force science” and does not

define “force science” anywhere in her briefing. Thus, it is unclear precisely which parts of Mr.

Allen’s report Plaintiff seeks to exclude. In response to Plaintiff’s motion to exclude, the United

States identifies and defends as admissible Mr. Allen’s opinion that a law enforcement officer’s

reaction time is longer when the officer has to engage in decision-making rather than simple

reaction tests involving only one response. In her reply brief, Plaintiff states that “[r]eaction time

of law enforcement is certainly interconnected with ‘the human brain’s capabilities.’” Thus, it

appears that this is at least one of the opinions Plaintiff intended to challenge in the motion to

exclude. Plaintiff did not identify or address any other opinions in the reply brief. Thus, the Court

considers only Plaintiff’s arguments generally and as they relate to the reaction-time opinion

identified by the United States.

A basic understanding of “force science” is necessary to proceed. “Force science” has been

explained by one expert as “the application of scientific principles, research, and testing to

confrontation in which force is used by police officers or others.” Garrit v. City of Chicago, No.

16-cv-7317, 2022 WL 124554, at *8 (N.D. Ill. Jan. 13, 2022). The District of Kansas has noted

“that the concept generally involves examining how scientific principles governing human

behavior apply to police work.” Finch v. City of Wichita, No. 18-1018-JWB, 2020 WL 3403121,

at *22 (D. Kan. June 19, 2020). Thus, “force science” appears to address issues at the intersection

of police work, training, and practice, and the human behavioral sciences. Based on review of

case law included herein, the Court notes that the border between opinions based on experience

and training as a police officer and opinions based on human behavioral sciences is rather

nebulous. While expert testimony must meet the threshold of admissibility under Daubert and

Rule 702, “[t]he rules for admissibility of expert testimony favor admission over exclusion.”

Roberson v. Kan. City S. Ry. Co., No. 4:22-cv-00358-RK, 2024 WL 4502924, at *3 (W.D. Mo.

Oct. 16, 2024) (citing Lauzon, 270 F.3d at 686).

Plaintiff Richardson argues, and Defendant United States concedes, that “[w]ithout

dismissing the field entirely, federal courts confronted with force science-based opinions have

routinely determined that witnesses with ‘force science’ training are not qualified to render

scientific opinions.” Garrit, 2022 WL 124554, at *8. Thus, courts have barred experts—whose

qualifications are limited to “force science” training—from “opin[ing] on the human brain’s

capabilities.” Id. Mr. Allen is currently employed as the “Director of Training and Senior

Instructor with the Force Science Institute.” However, this is not Mr. Allen’s only qualification

and not every opinion by someone associated with the Force Science Institute is inadmissible

merely because of such association.

Upon review, Mr. Allen’s opinion regarding reaction time does not appear to cross the line

into cognitive psychology, physiology, behavioral science, or any other purely scientific field.

Moreover, Mr. Allen’s opinion does not merely rely on his experiences at the Force Science

Institute but also on his 30 years of experience as a police officer, over 25 formal certifications,

relevant organization memberships, and review of publications on the issue of police perception

and reaction times. (Doc. 156 at 5-6.) Mr. Allen has also “conducted research on police

perception/reaction times, police response tactics, and visual attention processes and comparisons

with body work cameras.” (Id. at 6.) He has published five articles on these subjects in the past

ten years. (Id.) Thus, it appears that Mr. Allen’s area of expertise includes police reaction times

based on his experience as a police officer, his training, and his research. See Fed. R. Evid. 702

(noting a person may be “qualified as an expert by knowledge, skill, experience, training, or

education”).

In Finch v. City of Wichita, the court denied a motion to exclude expert testimony to the

extent the expert offered “testimony about reaction times of officers who decide to use force in

response to perceived threats.” 2020 WL 3403121, at *24. The court noted that the expert cited a

“study on officer reaction times” in support of his opinion, as well as his “own familiarity with

real world scenarios, reality-based training and the analysis of force encounters.” Id. (cleaned up).

The court concluded that this indicated the expert “has sufficient training, knowledge, and

experience to express an opinion about the amount of time it may take an officer to use force after

the officer sees a threat” but that “[t]his does not extend to discussions or opinions by [the expert]

about cognitive processes – just the amount of time it may take an officer to fire a weapon in

response to a threat.” Id.

Here, Mr. Allen offers an opinion regarding the perception or reaction time of an officer

responding to a threat, without opining about cognitive processes.8 His experience of 30 years as

a police officer, his over 25 formal certifications, and his experience at the Force Science Institute

combine to demonstrate his qualification to opine on this subject matter. Mr. Allen does not

8 It does not appear that Mr. Allen’s opinion on police reaction time goes beyond the limitation

recognized in Finch. To that extent, this Court finds the decision in Finch persuasive. Plaintiff, in failing

to point to specific opinions in Mr. Allen’s report, has not otherwise shown the Court that Mr. Allen’s

opinions go beyond what is permissible, consistent with Finch.

purport to rely on “force science” principles. See Zuniga v. City of Los Angeles, No. 2:22-cv-

03665-CBM-(ASx), 2024 WL 4744370, at *2 (C.D. Cal. Oct. 7, 2024) (denying motion to exclude

expert’s opinions to the extent they were based on “force science” principles because “no part of

Mr. Flosi’s expert report indicates that any of his opinions are based upon this information. The

Court finds that Mr. Flosi’s extensive background and experience in law enforcement qualifies him

to testify as to police practices and tactics, as Defendants’ expert disclosures state.”). Moreover,

like the expert in Finch, Mr. Allen conducted research on reaction times and cited at least five of

his own publications on the topic and nearly a dozen other published studies in his report. (Doc.

156-1 at 47-48.) Thus, based on the Court’s review of Mr. Allen’s expert report, the Court

concludes that it complies with the Daubert standard and Federal Rule of Evidence 702.

Plaintiff alternatively argues that Mr. Allen’s opinions relating to “force science” should be

excluded under Rule 403 as unduly prejudicial. Plaintiff argues that the jury “may give force

science too much weight over whether the DEA Agents Gasperoni and Stuart could have exercised

other options, such as obtaining an arrest warrant based on probable cause.” (Doc. 139 at 4

(emphasis added).) First, the Court notes this argument has little bearing on the specific opinion

identified in the briefing—that is, Mr. Allen’s opinion that officer reaction time is longer when the

officer must engage in decision-making. Second, the quoted language above is the entirety of

Plaintiff’s argument that the Court should exclude this evidence under Rule 403. The Court is not

persuaded that the value of the evidence is outweighed by any undue prejudice. Correspondingly,

this evidence that is unfavorable to Plaintiff does not establish undue prejudice.

Accordingly, Plaintiff Richardson’s motion to exclude Mr. Allen’s “force science” opinions

is DENIED.

B. Eyewitness Testimony Opinion

Second, Plaintiff Richardson seeks to exclude Mr. Allen’s opinions on eyewitness

testimony, particularly his opinion elicited by plaintiff counsel in his deposition that “police

officers involved in shootings can have specific, more precise memories of how the event unfurls

as opposed to a lay witness watching the incident.” (Doc. 139 at 5 (citing Doc. 139-2 at 6).)

Plaintiff argues that Mr. Allen has no supporting education, credentials, or background in the field

of memory and eyewitness testimony. Defendant United States counters that Mr. Allen’s opinion

on eyewitness testimony was only given because plaintiff counsel asked the question during Mr.

Allen’s deposition. The opinion does not appear in Mr. Allen’s expert report, and the United States

represents that it does not intend to elicit any such opinion from Mr. Allen on direct examination

at trial. To the extent plaintiff counsel questions Mr. Allen on the topic during cross-examination

at trial, the United States argues that such testimony should be allowed.

The Court finds that Plaintiff’s motion to exclude any “eyewitness testimony” opinion by

Mr. Allen is premature. See Charter Oak Fire Ins. v. SSR, Inc., No. 11-118-HRW, 2014 U.S. Dist.

LEXIS 185878, at *15 (E.D. Ky. Sept. 29, 2014) (finding motion to exclude expert opinion

premature where expert did not opine on the issue in his report and where counsel represented that

they did not intend for the expert to testify on the issue). Here, Mr. Allen did not include any

“eyewitness testimony” opinions in his report, and defense counsel states that they do not

anticipate eliciting any such opinions from him at trial. Instead, the only reason Mr. Allen has

opined on eyewitness testimony during the course of this litigation is because plaintiff counsel

asked Mr. Allen in his deposition, “[d]o you have some reason to believe that police officers who

are active participants in a shooting incident would have better memories of the shooting incident

than nonactive participants?” (Doc. 139-2 at 6.) The Court is persuaded by Defendant United

States’ argument that Mr. Allen should be able to respond to such questioning at trial, including

providing his opinion, should plaintiff counsel again open that door. See United States v. Bear,

920 F.3d 1199, 1202 (8th Cir. 2019) (“Having opened the door to this evidence, Spotted Bear

cannot now complain about its admission.”); Brown v. Muzyka, No. 6:23-cv-00474-ADA-DTG,

2025 WL 1873253, at *3 (W.D. Tex. May 22, 2025) (finding if plaintiff “opens the door to that

testimony by asking Mr. Irwin [defendant’s expert] about the Move Over or Slow Down law,

Plaintiff cannot later complain that Mr. Irwin’s testimony is objectionable or inadmissible”).

As set forth above, the Court finds Plaintiff Richardson’s motion to exclude eyewitness

testimony opinion premature, as Mr. Allen has not included any such opinions in his report and

defense counsel does not intend to elicit any such opinions on direct examination. Moreover,

because the admissibility of Mr. Allen’s opinions on eyewitness testimony may very well depend

on the nuances of how it is elicited, the Court declines to exclude Mr. Allen’s testimony at this

juncture. Therefore, Plaintiff’s motion to exclude the expert testimony of Craig Allen is DENIED.

Conclusion

Accordingly, after careful consideration and for the reasons explained above, the Court

ORDERS that (1) Defendant United States’ motion to exclude the expert testimony of Robert

Johnson, (Doc. 138), is GRANTED, and (2) Plaintiff Richardson’s motion to exclude the expert

testimony of Craig Allen, (Doc. 139), is DENIED.

IT IS SO ORDERED.

s/ Roseann A. Ketchmark

ROSEANN A. KETCHMARK, JUDGE

UNITED STATES DISTRICT COURT

DATED: March 2, 2026