In Re Estate of Guadalupe Lopez, Sr.

Supreme Court of Texas

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No. 24-0315

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In re Estate of Guadalupe Lopez, Sr., Deceased

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On Petition for Review from the

Court of Appeals for the Fourth District of Texas

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PER CURIAM

Justice Lehrmann did not participate in the decision.

“[T]he expert witness paints a powerful image on the litigation

canvas,” possessing a “vast potential for influence.” In re Christus

Spohn Hosp. Kleberg, 222 S.W.3d 434, 440 (Tex. 2007). The expert in

this case is a former family court judge who opined on the central

disputed issue in the case, testifying before the jury that, in her view,

the parties were informally married. She expressed that opinion

repeatedly and emphatically, though none of the relevant evidence was

technical, specialized, or otherwise beyond an ordinary person’s

understanding. Compounding the problem, she lent her opinion

credibility by explaining that she formed it using the same methodology

she employed when she presided over informal-marriage cases as a

judge. Unsurprisingly, the jury was persuaded and found an informal

marriage existed.

We hold that the trial court erred in admitting the expert’s

testimony and that the error was harmful, warranting a new trial. The

evidence was within the average juror’s common knowledge, so the

expert’s opinions did not help the jury as Rule of Evidence 702

contemplates. See TEX. R. EVID. 702. The expert instead improperly

opined on a legal presumption and explained that, if she were sitting as

the judge, she would find that the parties were informally married.

Mindful that the appearance of a judge as a witness carries the potential

both to sway the jury improperly and to “threaten[] . . . public confidence

in the integrity and impartiality of the judiciary,” Joachim v. Chambers,

815 S.W.2d 234, 238 (Tex. 1991) (quotation marks omitted), we conclude

that admitting this testimony amounted to harmful error. Accordingly,

we reverse the court of appeals’ judgment and remand the case to the

trial court for a new trial.

I

Guadalupe Lopez, Jr. (Lopez Junior) applied for independent

administration and an heirship determination after the death of his

father, Guadalupe Lopez, Sr. (Lopez Senior). The county court granted

the application and rendered judgment declaring Lopez Junior and his

two siblings heirs of their father’s estate. Elvira Gonzalez later filed a

petition for bill of review, alleging she was Lopez Senior’s common-law

wife and seeking a judgment declaring her an heir.

The trial court withheld ruling on the bill of review until after a

jury determined whether Lopez Senior and Gonzalez were informally

married. To support her claim that they were, Gonzalez offered the

expert testimony of Alicia York, a former district court judge. Over

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Lopez Junior’s objections, the trial court admitted Judge York’s

videotaped deposition testimony in which she told the jury that

Gonzalez “clearly . . . show[ed] that all three elements of common-law

marriage existed.” The jury found that Lopez Senior and Gonzalez were

married, and the trial court rendered judgment granting the bill of

review and awarding Gonzalez a share of Lopez Senior’s estate.

Lopez Junior appealed, challenging, among other things, the

admission of Judge York’s testimony. The court of appeals affirmed. ___

S.W.3d ___, 2024 WL 946236, at *1 (Tex. App.—San Antonio Mar. 6,

2024). The court did not decide whether the trial court abused its

discretion in admitting Judge York’s testimony. It instead offered four

reasons why any error was harmless: (1) the testimony was cumulative;

(2) none of Judge York’s opinions “articulated improper legal concepts”;

(3) Gonzalez did not emphasize Judge York’s testimony; and (4) the

other evidence supporting Gonzalez’s claim comfortably “withstood

Lopez Junior’s factual sufficiency challenge.” Id. at *9-10.

Lopez Junior petitioned this Court for review.

II

We review a trial court’s admission of evidence for an abuse of

discretion. Serv. Corp. Int’l v. Guerra, 348 S.W.3d 221, 235 (Tex. 2011);

In re J.P.B., 180 S.W.3d 570, 575 (Tex. 2005). A qualified expert may

testify if their “specialized knowledge will help the trier of fact to

understand the evidence or to determine a fact in issue.” TEX. R.

EVID. 702. Because an expert’s testimony does not help the jury unless

“the expert’s knowledge and experience on a relevant issue are beyond

that of the average juror,” K-Mart Corp. v. Honeycutt, 24 S.W.3d 357,

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360 (Tex. 2000), a trial court should exclude an expert’s testimony

“[w]hen the jury is equally competent to form an opinion about the

ultimate fact issues or the expert’s testimony is within the common

knowledge of the jury,” id.; cf. Guevara v. Ferrer, 247 S.W.3d 662, 665

(Tex. 2007) (“The general rule has long been that expert testimony is

necessary to establish causation as to medical conditions outside the

common knowledge and experience of jurors.”). If expert testimony is

unhelpful, it is inadmissible, and the trial court errs by allowing it. See

Dall. Morning News, Inc. v. Hall, 579 S.W.3d 370, 379 (Tex. 2019).

Erroneous admission of expert testimony is harmless—and thus

not grounds for reversal—“unless the error probably (though not

necessarily) caused rendition of an improper judgment.” Reliance Steel

& Aluminum Co. v. Sevcik, 267 S.W.3d 867, 871 (Tex. 2008); see TEX. R.

APP. P. 61.1(a). An error is harmful if it “contributed in a substantial

way to bring about the adverse judgment.” Gunn v. McCoy, 554 S.W.3d

645, 668 (Tex. 2018) (quoting Lorusso v. Members Mut. Ins. Co., 603

S.W.2d 818, 820 (Tex. 1980)). Admission of improper evidence can be

harmful even if there is other legally sufficient evidence supporting the

verdict. See Kia Motors Corp. v. Ruiz, 432 S.W.3d 865, 884 (Tex. 2014).

To determine whether the error is harmful, “we evaluate the

entire case from voir dire to closing argument, considering the evidence,

strengths and weaknesses of the case, and the verdict.” Guerra, 348

S.W.3d at 236. Relevant factors include “the role the evidence played in

the context of the trial,” Sevcik, 267 S.W.3d at 873, “whether counsel

emphasized the erroneous evidence,” Guerra, 348 S.W.3d at 236,

“whether the admission of the evidence was calculated or inadvertent,”

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id., and “whether contrary evidence existed that the improperly

admitted evidence was calculated to overcome,” U-Haul Int’l, Inc. v.

Waldrip, 380 S.W.3d 118, 136 (Tex. 2012). The error is likely harmless

if the admitted evidence was cumulative “or if the rest of the evidence

was so one-sided that the error likely made no difference.” Sevcik, 267

S.W.3d at 873. By contrast, the error is likely harmful if the evidence

“was crucial to a key issue.” Id. See generally Jackson v. Takara, 675

S.W.3d 1, 6-7 (Tex. 2023); In re Est. of Poe, 648 S.W.3d 277, 285-86 (Tex.

2022); Caffe Ribs, Inc. v. State, 487 S.W.3d 137, 145 (Tex. 2016).

III

It was error to admit Judge York’s expert testimony. The issue

on which she opined—whether the evidence established an informal

marriage—was within the average juror’s knowledge. See TEX. R.

EVID. 702; K-Mart, 24 S.W.3d at 360 (“When the jury is equally

competent to form an opinion about the ultimate fact issues or the

expert’s testimony is within the common knowledge of the jury, the trial

court should exclude the expert’s testimony.”). The elements needed to

prove an informal marriage—that the couple agreed to be married, lived

together as husband and wife after the agreement, and represented to

others that they were married, see TEX. FAM. CODE § 2.401(a)(2)—are

not specialized or otherwise beyond the understanding of an ordinary

juror. Gonzalez notably makes no argument as to why “specialized

knowledge,” TEX. R. EVID. 702, is necessary to determine whether the

evidence shows an informal marriage existed. See Dall. Morning News,

579 S.W.3d at 379.

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To the extent Judge York offered insights that could be regarded

as specialized or beyond common knowledge, it was in the form of

impermissible testimony about the law. See In re Ayad, 655 S.W.3d 285,

288 n.1 (Tex. 2022); TEX. R. EVID. 702-704. For example, Judge York

testified at length about a Family Code presumption and how the jury

should apply it when reviewing the evidence. It is the trial court’s role—

not that of the expert witness—“to define the particular legal principles

applicable to a case.” Greenberg Traurig of N.Y., P.C. v. Moody, 161

S.W.3d 56, 95 (Tex. App.—Houston [14th Dist.] 2004, no pet.); see also

id. at 99 (“By permitting attorneys to state opinions as to what the

applicable law is, the trial judge voluntarily allows his role as the legal

expert in the courtroom to be usurped or diminished by the testifying

attorney.”).

Rather than help the jury understand subject matter beyond

common knowledge, Judge York’s testimony served only the improper

purpose of providing “an official endorsement” favoring Gonzalez’s

position. See Joachim, 815 S.W.2d at 238. She emphasized that she

formed her opinions “wearing [her] judge’s hat” and explained that on

the evidence presented, based on her experience presiding over 5,000

family-law trials, Gonzalez should win. The trial court thus erred in

admitting Judge York’s testimony.1

1 While courts must be mindful of the unique concerns that arise when

a former judge testifies as an expert witness, see Joachim, 815 S.W.2d at 239,

we do not hold that former judges are categorically prohibited from testifying

as experts. For example, testifying about the reasonableness of a party’s claim

for attorney’s fees is a proper subject for expert testimony and does not subject

the jury to the expert’s judicial views to the extent that the testimony here did.

But even in cases in which a former judge’s expert testimony is admissible,

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We also conclude that the error was harmful—that it “contributed

in a substantial way to bring about the adverse judgment.” Gunn, 554

S.W.3d at 668 (quoting Lorusso, 603 S.W.2d at 820). Indeed, all the

relevant factors in the harm analysis point toward this conclusion.

First, Judge York’s testimony was crucial to the only contested

issue in the case, on which the evidence cut both ways. See Sevcik, 267

S.W.3d at 873 (“[I]f erroneously admitted . . . evidence was crucial to a

key issue, the error was likely harmful.”). While there is evidence in the

record from which the jury could have found an agreement to be

married—for example, photos of Lopez Senior wearing a wedding ring,

two quinceañera invitations for Gonzalez’s daughters identifying Lopez

Senior and Gonzalez as “Mr. & Mrs. Lupe Lopez,” and a tax form and

warranty deed identifying them as married—the record also contains

contrary evidence. For example, Lopez Senior and Gonzalez never had

a joint bank account, and documentary evidence (tax forms, employment

records, and car insurance) showed they identified themselves as

“single.” And there was testimony that Lopez Senior referred to another

woman as his “fiancée” during the time Gonzalez claimed to be his wife.

It is thus far from clear whether the jury would have found an

agreement absent Judge York’s testimony as to how she would have

weighed the competing evidence in her capacity as a judge. The fact that

the evidence was not one-sided makes it more likely the jury relied on

trial courts, counsel, and the witness should avoid repeated touting and

emphasis of the expert’s status as a former judge of the sort apparent in this

record. See id. (“The entrance of a judge into the litigation arena in aid of a

combatant impacts not only the outcome of that conflict but the very idea of

judicial impartiality.”).

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her opinion in reaching its verdict. See Christus Spohn Hosp., 222

S.W.3d at 440 (“[T]he expert is generally held out to be, and is seen by

the jury as, an objective authority figure more knowledgeable and

credible than the typical lay witness.”).

Second, we disagree with the court of appeals’ conclusion that

much of Judge York’s testimony was cumulative. See 2024 WL 946236,

at *9. Her testimony did more than merely restate or summarize the

evidence—she provided her own spin on how the jury should weigh

competing evidence on the only issue it was asked to decide. Cf. Bagheri

v. State, 119 S.W.3d 755, 763-64 (Tex. Crim. App. 2003) (concluding that

the effect of an expert’s testimony regarding a defendant’s intoxication

“was almost certainly to tip the balance in favor of the State,” so the

expert’s erroneously admitted testimony was not cumulative despite

other evidence that the defendant was intoxicated). Judge York was the

only expert to testify on the informal-marriage issue. See State v.

Dawmar Partners, Ltd., 267 S.W.3d 875, 881 (Tex. 2008) (concluding

that the challenged experts’ testimony “was cumulative of substantially

similar [testimony] from another expert”); Mancorp, Inc. v. Culpepper,

802 S.W.2d 226, 230 (Tex. 1990) (concluding that the challenged expert’s

testimony was cumulative of similar testimony from six other experts).

Nor is this a case where “an abundance of evidence” otherwise supports

the finding the expert advanced. GTE Sw., Inc. v. Bruce, 998 S.W.2d

605, 620 (Tex. 1999); see also Sevcik, 267 S.W.3d at 873 (noting that the

erroneous admission of evidence is likely harmless if “the rest of the

evidence was so one-sided that the error likely made no difference”). As

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detailed above, the evidence conflicted, and Judge York told the jury that

Gonzalez should win.

Third, Gonzalez’s use of Judge York’s testimony was “calculated,”

not “inadvertent.” Sevcik, 267 S.W.3d at 874; see also U-Haul Int’l, 380

S.W.3d at 136 (“[Plaintiff]’s advocacy for inclusion of this testimony, over

objection, suggests it was a significant element of this case.”); Sevcik,

267 S.W.3d at 874 (“[A] party’s insistence on introducing inadmissible

testimony ‘indicates how important he thought it was to his case.’”

(quoting Alvarado v. Farah Mfg. Co., 830 S.W.2d 911, 917 (Tex. 1992))).

Finally, we disagree with the court of appeals and Gonzalez that

the evidence was not emphasized. See 2024 WL 946236, at *10. We

have previously rejected arguments that prejudicial evidence was

harmless merely because it was mentioned only once, observing “[i]f that

were the only rule, there would be little use for the rules of evidence as

everyone could ignore them once with impunity.” Sevcik, 267 S.W.3d at

873-74. Here, Judge York was introduced to the jury as a former

family-law judge, and that role was emphasized throughout her

testimony.

IV

The trial court abused its discretion by admitting the testimony

of a former judge as an expert witness when (1) the expert’s opinion was

not beyond common knowledge and therefore did not help the jury as

Rule of Evidence 702 contemplates and (2) the expert emphasized that

her opinion was the finding she would make if she were the judge in this

case. The error was harmful because the improperly admitted evidence

was not cumulative and the ultimate issue for the jury was hotly

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contested, with the parties offering sharply conflicting evidence in

support of their respective positions. Accordingly, without hearing oral

argument, we grant the petition for review, reverse the court of appeals’

judgment, and remand the case to the trial court for a new trial. See

TEX. R. APP. P. 59.1.

OPINION DELIVERED: November 7, 2025

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