134 April 5, 2023 No. 162

IN THE COURT OF APPEALS OF THE

STATE OF OREGON

STATE OF OREGON,

Plaintiff-Respondent,

v.

STEPHANIE ANDREA ORTIZ,

Defendant-Appellant.

Josephine County Circuit Court

20CR23850; A175738

Brandon S. Thueson, Judge.

Submitted October 4, 2022.

Ernest G. Lannet, Chief Defender, Criminal Appellate 

Section, and Peter G. Klym, Deputy Public Defender, Office 

of Public Defense Services, filed the brief for appellant.

Ellen F. Rosenblum, Attorney General, Benjamin Gutman, 

Solicitor General, and Erica L. Herb, Assistant Attorney 

General, filed the brief for respondent.

Before Shorr, Presiding Judge, and Mooney, Judge, and 

Pagán, Judge.

SHORR, P. J.

Reversed and remanded.

Pagán, J., dissenting.
Cite as 325 Or App 134 (2023) 135

SHORR, P. J.

Defendant appeals from a judgment of conviction 

for one count of driving under the influence of intoxicants 

(DUII), ORS 813.010(4). On appeal, she asserts that the trial 

court plainly erred when it failed to strike testimony by the 

arresting officer that field sobriety tests (FSTs) that the officer administered to defendant were scientifically validated 

and erred again when it permitted the officer to testify that 

defendant’s performance on the FSTs was consistent with 

intoxication and not with sobriety. Defendant asserts that 

the officer’s testimony was scientific evidence for which the 

state failed to lay an adequate foundation. For the reasons 

that follow, we reverse and remand.

In reviewing a trial court’s evidentiary ruling, “we 

do so in light of the record that was before the court at the 

time of the ruling.” State v. Eatinger, 298 Or App 630, 632, 

448 P3d 636 (2019). When evaluating whether the erroneous 

admission of evidence was harmless, we consider all pertinent parts of the record. Id. A complete recitation of those 

facts would not benefit the bench, the bar, the public, or the 

parties, and thus we provide only a general recitation below.

At trial, the state presented evidence that a concerned citizen called 9-1-1 to report that she had just heard 

a vehicle “screech” to a stop, prompting her to look out the 

window and observe a white SUV in her neighbor’s driveway 

“at an odd angle.” Because of the orientation of the vehicle, 

the witness believed it had been traveling in the wrong lane 

of traffic before entering the driveway. The witness provided 

a detailed description of the driver.

Officer Miguel arrived at the location and approached

defendant, who matched the description of the driver given 

by the witness. In speaking to defendant, Miguel “could smell 

the odor of an alcoholic beverage coming from her breath” 

and noticed that defendant had “watery eyes.” Defendant 

also “had cyclical mood cycles [and] would range from being 

angry to crying to laughing.” Defendant told Miguel that 

she was “a little bit tipsy,” that “she did not believe that she 

was safe to drive,” and that she had had “five beers” over the 

course of six to seven hours. She denied driving the vehicle.
136 State v. Ortiz

Miguel proceeded to investigate defendant for DUII 

and asked her to perform two FSTs: a “walk-and-turn” test 

and a “one-leg-stand” test. After noting several “clues” from 

defendant’s performance on the FSTs, Miguel arrested defendant for DUII.

Miguel testified at trial, without objection, that the 

FSTs are “designed to determine impairment,” nationally 

“standardized,” and supported by studies “prov[ing] their 

validity.” Miguel then described the tests in detail, including the instructions she gave to defendant regarding the 

tests and defendant’s subsequent performance on the tests. 

Miguel testified that defendant “showed five out of eight 

clues” on the walk-and-turn test and “three of four” possible 

clues on the one-leg-stand test.

Miguel’s bodycam footage, which showed her interview of defendant and defendant’s performance on the FSTs, 

was admitted into evidence and played for the jury. The jury 

was also presented with evidence that defendant submitted 

to a breath test, which measured her blood alcohol content 

(BAC) at .07 percent just over one hour after the officer initially received the concerned citizen’s call.

In her defense, defendant testified that her husband, 

rather than she, had been driving. Defendant admitted that 

she had been drinking and that she had told Miguel that 

she had not felt safe to drive. Defense counsel argued in closing, however, that, based on all of the evidence, the jurors 

could find defendant not guilty either because they found 

that she had not been driving, or, if they found she had been 

driving, because they concluded that she had not been under 

the influence of intoxicating liquor “to the extent that she 

could not safely operate that vehicle.” Among other arguments, defense counsel argued that defendant’s poor performance on the FSTs could have been caused by defendant’s 

emotional state or embarrassment rather than intoxication.

The jury returned a unanimous guilty verdict. Defendant was convicted of driving under the influence of intoxicants, ORS 813.010(4), and this timely appeal followed. We 

review for legal error whether evidence is “scientific,” and, if 

so, whether it is admissible. State v. Ohotto, 261 Or App 70, 

71, 323 P3d 306 (2014).
Cite as 325 Or App 134 (2023) 137

We begin by considering defendant’s argument that 

the trial court plainly erred in not excluding Miguel’s testimony that the FSTs administered to defendant were scientifically validated, and because we conclude that the court 

plainly erred in that regard and that exercising our discretion to correct the error is appropriate, we do not reach 

defendant’s other assignment of error.

We agree with the parties that defendant’s assignment of error was unpreserved and thus turn to our established plain-error inquiry. Plain-error review involves a 

two-step inquiry in which we first determine whether the 

error is plain, and second, whether to exercise our discretion 

to consider the error. ORAP 5.45; Ailes v. Portland Meadows, 

Inc., 312 Or 376, 381-82, 823 P2d 956 (1991). To constitute 

plain error, the error must be (1) one of law, (2) obvious, i.e., 

not reasonably in dispute, and (3) “apparent on the record 

without requiring the court to choose among competing 

inferences.” State v. Vanornum, 354 Or 614, 629, 317 P3d 

889 (2013).

As the court explained in State v. O’Key, 321 Or 285, 

291, 899 P2d 663 (1995), “[e]vidence perceived by lay jurors 

to be scientific in nature possesses an unusually high degree 

of persuasive power. The function of the court is to ensure 

that the persuasive appeal is legitimate.” (Footnote omitted.) Hence, “in the absence of a clear case, a case for judicial 

notice, or a case of prima facie legislative recognition,” id. at 

293 (footnote omitted), the trial court must assess the scientific validity of proffered scientific evidence by considering 

the potential factors outlined in State v. Brown, 297 Or 404, 

417, 687 P2d 751 (1984), and O’Key, 321 Or at 299-306. The 

proponent of the evidence must lay an adequate foundation 

addressing the Brown/O’Key factors. State v. Trujillo, 271 Or 

App 785, 791, 353 P3d 609, rev den, 358 Or 146 (2015).

Because the state did not lay such a foundation 

here, the questions before us are whether Miguel’s testimony constituted “scientific” evidence and whether the trial 

court plainly erred in not sua sponte excluding it as such. We 

have previously stated that “[e]vidence qualifies as scientific when it is expressly presented to the jury as scientific, 

when it draws its convincing force from scientific principles, 
138 State v. Ortiz

or when it would likely be perceived by the jury as imbued 

with the persuasive appeal of science.” State v. Reid, 312 Or 

App 540, 543, 492 P3d 728 (2021) (internal quotation marks 

omitted).

We readily conclude that Miguel’s testimony was 

scientific evidence. In Eatinger, we determined that an officer’s testimony that FSTs are scientifically validated and 

“the product of scientific research” was scientific, “because it 

purported to draw its convincing force from principles of science” rather than the officer’s training and experience. 298 

Or App at 631, 642. Similarly in State v. Beltran-Chavez, 

286 Or App 590, 614, 400 P3d 927 (2017), we determined 

that an officer’s testimony that the defendant “passed” or 

“failed” the walk-and-turn and one-leg-stand FSTs was scientific evidence, because “the proposition underlying that 

testimony is that the test is able to measure impairment 

objectively and that a specific numerical score can prove 

that the subject is impaired.”

Here, Miguel testified that the FSTs were “designed 

to determine impairment,” nationally “standardized,” and, 

perhaps most concerning, supported by studies “prov[ing] 

their validity.” That testimony is functionally indistinguishable from the evidence considered in Eatinger and BeltranChavez. We thus reject the state’s contention that the evidence at issue was not “plainly scientific.” Because the state 

did not attempt to lay an adequate Brown/O’Key foundation, 

it would be error for a trial court to admit the above testimony over an appropriate objection.

We appreciate the dissent’s position that Miguel’s 

testimony that the FSTs were “designed to determine 

impairment” may not, standing alone, constitute scientific 

testimony. 325 Or App at 148 (Pagán, J., dissenting). It is 

difficult to understand that testimony as meaningfully different than an officer’s testimony that FSTs can be “passed” 

or “failed,” which we concluded was scientific testimony in 

both Beltran-Chavez and, as discussed further below, Reid. 

See Beltran-Chavez, 286 Or App at 614; Reid, 312 Or App 

at 543. But we need not decide this case on those words 

alone. As noted, in addition to testifying that the FSTs were 

“designed to determine impairment,” the officer also testified 
Cite as 325 Or App 134 (2023) 139

that the tests were nationally “standardized” and that they 

were supported by studies “prov[ing] their validity.” That is 

testimony that derives its force from scientific principles—it 

presents a jury with the contention that a national standard 

has not only been developed, but that studies have determined that the tests produce scientifically valid evidence of 

impairment. All of that testimony together presented the 

jury with the impression that the FSTs were derived from, 

proved by, or, at a minimum, imbued with the persuasive 

appeal of science.1

As noted, defendant did not object to Miguel’s testimony. We therefore turn to whether it was plain error for 

the trial court to not recognize the testimony as obviously 

scientific testimony lacking a foundation and, accordingly, 

sua sponte exclude its admission into evidence.

Based on our recent decision in Reid, we conclude 

that that error was plain and that the trial court had a duty 

to exclude the evidence. In Reid, an officer testified that the 

FSTs are “pass or fail” tests. 312 Or App at 543. The defendant did not object to that testimony. Id. On appeal, the state 

conceded “that plain-error review and reversal would be 

appropriate.” Id. at 541. We accepted the state’s concession. 

Id. Although our plain-error analysis was not extensive, we 

highlighted that the officer’s pass/fail testimony was nearly 

identical to the testimony in Beltran-Chavez. We then concluded, based on Beltran-Chavez, that it was “obvious [and] 

not reasonably in dispute” that it was legal error to admit 

that scientific testimony without a proper foundation. Id. at 

543-44.

The necessary implication from Reid is that a trial 

court has a sua sponte duty to exclude clearly scientific testimony regarding FSTs when it is presented without a proper 

foundation. As discussed above, the testimony at issue here, 

which included testimony that the FSTs were supported by 

studies proving their validity, was similarly—if not more 

obviously—scientific testimony than that at issue in Reid. 

1 Of course, jurors may be presented with scientific evidence. As we note 

above, however, due to the inherently persuasive appeal of evidence that is perceived by jurors as scientific, the court must first assess the scientific validity of 

such evidence before permitting its admission. O’Key, 321 Or at 291-92.
140 State v. Ortiz

By testifying that FSTs are standardized tests that are 

designed to measure impairment and validated through 

studies, Miguel imbued her testimony with the persuasive 

authority of science.

The dissent contends that we are creating new law 

through this decision and questions why we would create 

a new sua sponte duty for trial courts to strike such testimony.2

 325 Or App at 151-53 (Pagán, J., dissenting). 

Respectfully, our decision is controlled by Reid, which held 

that it was plain error for a trial court to admit scientific 

testimony that FSTs are pass or fail tests, even when, as in 

all plain error cases, the party opposing admission did not 

object. By concluding that there was plain error in those circumstances, Reid necessarily requires trial courts to strike 

such testimony.

Further, as we did in Reid, we also exercise our discretion to correct the error. Id. at 544 (stating that “we perceive no reasons why our exercise of discretion to correct the 

error is not appropriate”). We first note that we do not agree 

with the state’s contention that there is little likelihood that 

Miguel’s erroneously admitted testimony affected the verdict.3 See State v. Davis, 336 Or 19, 32, 77 P3d 1111 (2003) 

(describing harmless-error inquiry). Here, defendant’s BAC 

was under the per se limit when tested approximately one 

hour after the initial call to the police. The state needed 

to prove that defendant drove while her “physical or mental faculties were adversely affected to a noticeable or perceptible degree.” State v. Miller, 265 Or App 442, 445, 335 

P3d 355 (2014). Thus, the state needed to prove both that 

defendant had been the driver of the vehicle and that she 

2 Although we respectfully disagree with the dissent on the merits, we appreciate that it may be appropriate to probe whether a trial court should have a sua 

sponte duty to strike clearly scientific testimony. There are arguments pointing 

in each direction. Our decision in Reid did not directly confront those arguments. 

It may be that the Supreme Court ultimately addresses the issue. In the meantime, however, Reid constitutes controlling case law for our court, and in the 

absence of argument from the parties that Reid was wrongly decided, the principles of stare decisis require that we follow that controlling law.

3 The state contends that any error was harmless, and that we should affirm 

on that basis. The state also separately contends that, because any error was 

harmless, we should not exercise our discretion correct it. As discussed below, we 

reject both contentions.
Cite as 325 Or App 134 (2023) 141

had been adversely affected while doing so. Defendant contested both elements at trial. And, although the state is correct that other evidence in the record could have supported 

a jury finding that defendant was impaired at the time of 

the incident—including, notably, defendant’s own admission 

that she did not believe she was safe to drive—that alone 

is insufficient to render the court’s error harmless. As in 

Eatinger, Miguel’s testimony that the FSTs were scientifically validated “presented the jury with evidence that had 

persuasive value apart from [other evidence] that defendant 

was impaired.” 298 Or App at 646. And, as we concluded in 

Beltran-Chavez, Miguel’s testimony “presented the jury with 

a separate, ostensibly objective, reason to believe that defendant was under the influence.” 286 Or App at 618 (emphasis added). We further observe that the state emphasized 

and relied on the FST results in its closing argument. That 

emphasis leaves us unable to conclude that the testimony 

bore “no relationship to the jury’s determination of its verdict” or was “duplicative or unhelpful to its deliberations.” 

Davis, 336 Or at 32-33.

The dissent notes some of the additional persuasive 

evidence that may have nevertheless caused the jury to convict in this case, and suggests that, even assuming there 

was error, any is harmless. 325 Or App at 150-51 (Pagán, J.,

dissenting). But our job is not to reweigh the evidence or 

decide whether that other evidence was substantial when 

balanced against the improperly admitted evidence. We 

have rejected similar arguments in the past:

“[T]he state’s request, which calls for us to consider the 

‘overwhelming’ evidence of guilt and balance it against the 

probative value and credibility of defendant’s proffered testimony, invites us to reweigh the evidence. That is not our 

task when we conduct a harmless-error analysis. In conducting that analysis, we focus on the possible influence of 

the error on the verdict rendered, not whether this court, 

sitting as a factfinder, would regard the evidence of guilt as 

substantial and compelling.”

State v. Zaldana-Mendoza, 299 Or App 590, 613, 450 P3d 

983 (2019) (internal quotation marks omitted). We focus 

here on whether the improperly admitted scientific evidence 

had little likelihood of affecting the verdict. As noted above, 
142 State v. Ortiz

due to the inherently persuasive effect of scientific evidence 

and the prosecution’s focus on the FST results in its closing 

argument, we cannot say that the testimony at issue had 

little likelihood of affecting the verdict.4

Finally, we are not persuaded that exercising our 

discretion in this case is inappropriate because of defendant’s failure to object to Miguel’s scientific testimony. 

Although the state posits that it could have laid an adequate 

foundation had defense counsel appropriately objected, we 

are not so sure—Miguel was a police officer who did not 

testify to possessing any special scientific knowledge and 

who referenced her police academy training, “wet lab” experience, and prior DUII investigations when asked to detail 

her training regarding FSTs. Thus, it is difficult to see how 

the state could have laid an adequate Brown/O’Key foundation for Miguel to testify as a scientific expert had defense 

counsel objected to the evidence. Cf. State v. Garcia, 320 

Or App 123, 138, 512 P3d 839, rev den, 370 Or 602 (2022) 

(“[n]othing suggests that, if defendant had objected, the 

state would have been unable to successfully address the 

objection and secure admission of the same testimony”).

In conclusion, the trial court plainly erred in not 

excluding Miguel’s testimony that the FSTs were “designed 

to determine impairment,” nationally “standardized,” and 

supported by studies “prov[ing] their validity.” That error 

was not harmless. We also exercise our discretion to correct that error. Because we reverse and remand for a new 

trial, we need not address defendant’s contention that the 

trial court also erred in permitting Miguel to testify that 

defendant’s performance on the FSTs was consistent with 

other indicators of impairment and inconsistent with how 

a sober person would perform. However, because the issue 

could occur again on remand, we reiterate, as we have said 

in other cases, that an officer may testify to their opinion 

regarding a defendant’s intoxication without establishing a 

4 We also note that we see this as a closer case than the dissent. Of course, 

the jury heard significant evidence that could lead it to conclude that defendant 

drove while impaired. But, as noted, the jury also heard evidence that defendant’s breath test indicated a .07 percent BAC. That is below the per se legal limit 

for DUII, ORS 813.010(1)(a), and the video evidence of defendant’s impairment is 

also not overwhelming.
Cite as 325 Or App 134 (2023) 143

scientific foundation, even if that opinion is in part based on 

scientific evidence, if the opinion “draws its force from [the 

officer’s] training and experience” and “does not imply that 

it is based on science.” Beltran-Chavez, 286 Or App at 603-

04; State v. Rambo, 250 Or App 186, 195, 279 P3d 361 (2012), 

rev den, 353 Or 203 (2013).

Reversed and remanded.

PAGÁN, J, dissenting.

“Under our adversary system, once a defendant 

has the assistance of counsel the vast array of trial decisions, strategic and tactical, which must be made before and 

during trial rests with the accused and his attorney. Any 

other approach would rewrite the duties of trial judges and 

counsel in our legal system.” Estelle v. Williams, 425 US 501, 

512, 96 S Ct 1691, 48 L Ed 126 (1976). When an appellate 

court exercises its discretion to correct plain error regarding testimony or evidence, it communicates to trial judges 

that they should be ready to intervene sua sponte on a regular basis during trials, regardless of the potential tactical 

decisions the parties have made for themselves. While there 

may be circumstances that warrant such a transformation 

from jurist to advocate—such as unequivocal vouching—

it behooves us to restrict the expansion of such a doctrine 

beyond what is absolutely necessary to ensure that litigants 

enjoy fair trials. I dissent from the majority because I disagree that any error occurred below, and if there was error, 

it was harmless. But I also dissent to the extent the majority 

is comfortable with expanding the doctrine of requiring sua 

sponte striking of testimony beyond unequivocal vouching.

Relying on the plain-error doctrine, the majority 

reverses defendant’s conviction, after a jury trial, for driving while under the influence of intoxicants (DUII), ORS 

813.010(4). But the error was not plain, and we should not 

exercise our discretion to consider it. By doing so, the majority creates a new rule for trial judges, imposing a new sua 

sponte duty to strike testimony about the purpose of field 

sobriety tests (FSTs), whether they are nationally standardized, and why police officers use them, despite allowing officers to then testify about the tests and how the officers utilized them. That new rule is confusing, inherently 
144 State v. Ortiz

contradictory, exceedingly difficult to enforce, and I disagree with the majority’s suggestion that our prior cases 

compel us to adopt it. In addition, the claimed error, if any, 

was harmless.

The state charged defendant with the misdemeanor 

offense of DUII, ORS 813.010(4). At defendant’s jury trial, 

the state called two witnesses: the person who made a 9-1-1 

call, and the police officer who responded. The first witness 

testified that she made the call because she heard a vehicle 

screech to a halt, and the witness saw a man pull a woman 

out of the driver’s side of the vehicle.

Officer Miguel, a police officer with the City of 

Grants Pass, responded to the 9-1-1 call. Miguel located “a 

male, female and juvenile matching the exact description 

provided” by the witness who made the 9-1-1 call. Miguel 

made an in-court identification of defendant as the woman 

with whom she spoke. Miguel was initially investigating 

the incident as one of domestic violence. But when Miguel 

learned that defendant may have been driving, Miguel “continued forward with a DUI investigation.”

Miguel “could smell the odor of an alcoholic beverage” coming from defendant’s breath, and defendant had 

“watery eyes.” Miguel testified regarding other “indicators 

of impairment,” including that defendant “was emotional, 

she had cyclical mood cycles ** * rang[ing] from being angry 

to crying to laughing, [and] she was quickly annoyed with 

certain questions.” Miguel testified that defendant “had 

even offered to me that she was feeling a little bit tipsy.” 

Defendant told Miguel that she did not believe that she was 

safe to drive. Defendant said that she drank five beers that 

day. When asked by the officer to rate her intoxication on a 

scale of one to 10, with one being completely sober, and 10 

being falling down drunk, defendant rated herself as a four. 

Defendant told the officer that “she was not wearing underwear because she had previously urinated herself during 

the day.”

Regarding FSTs, the prosecutor asked the officer 

whether she had “received any specific training in administering” them. Miguel responded that she had. The prosecutor asked for an explanation of “the purposes” of FSTs. 
Cite as 325 Or App 134 (2023) 145

Miguel responded, “They are divided attention tests. They 

are designed to determine impairment.” Miguel required 

defendant to perform “the walk-and-turn test and the oneleg stand.” When asked whether “those tests [are] used by 

law enforcement around the country,” Miguel responded, 

“Yes. Those are standardized tests.” The prosecutor asked, 

“Why are those tests used around the country?” Miguel 

responded, “Like I said, they are standardized. There have 

been studies conducted to prove their validity. There—it’s 

a national standard, so it’s not just something that I made 

up or anybody in my department made up. It is a national 

standardized test. It is conducted the same way, it has the 

same set of instructions, same set of rules for each person 

that performs that nationwide.”

Regarding her training, Miguel explained that, in 

the basic academy, she took a course called, “Standardized 

Field Sobriety Tests.” Miguel participated in a “wet lab,” 

which involved performing the tests on volunteers who had 

been drinking. Miguel passed the training, and she had 

experience conducting several DUII investigations for drugs 

and alcohol.

Miguel described the walk-and-turn test, and when 

defendant performed the test, Miguel observed “five out of 

eight clues” of impairment. Shortly thereafter the following 

exchange occurred:

“Q And you had already said, but let’s go over it again—

how many clues did the Defendant display?

“A Five out of eight.

“Q Was that consistent with her statements that she was 

unsafe to drive?

“A Yes.

“Q Was that consistent with the odor of alcohol you 

smelled?

“A Yes.

“Q Was that consistent with her watery eyes?

“A Yes.

“Q Was that consistent with her mood swings?
146 State v. Ortiz

“A Yes.

“Q Was that consistent with the erratic driving you 

learned about?

“A Yes.

“Q Please compare for the jury what you observed the 

Defendant do with what you would expect a sober person 

to do.

“A The test, as it’s explained—

“[DEFENSE COUNSEL]: Your Honor, I’m going to object 

as to foundation and speculation. I don’t think that—

“[PROSECUTOR]: It’s (indiscernible) training and experience and the opinion she formed in the course of her 

duties.

“THE COURT: Yeah. Overruled.

“THE WITNESS: I can explain? Can you say the question one more time?

“Q Please compare for the jury what you observed the 

Defendant do with what you would expect a sober person 

to do.

“A So, I would expect a sober person who has never seen 

those tests before, never performed them in their life, I 

would definitely not expect them to demonstrate five out 

of eight clues. These tests are not difficult. They are very 

basic. I give the instructions very clearly. I repeat multiple key points of the instructions, multiple times. So, if 

there’s—I give the person [an] opportunity to ask questions. 

I confirm with them that they understand the test before 

they begin it. So, if they have any questions about what 

they saw or what I demonstrated, or if they weren’t listening, got distracted by something, they have the opportunity 

right there to ask me before they perform the test. So, there 

shouldn’t really be a reason why there’s that many indicators of impairment if you’re completely sober.”

Next, the officer described the one-leg stand test 

and her training and experience administering it. On 

that test, defendant exhibited three out of four clues. After 

performing the two tests, Miguel placed defendant under 

arrest. The jury watched excerpts from the body camera 

footage of Miguel’s encounter with defendant, including 
Cite as 325 Or App 134 (2023) 147

video of defendant’s performance on the two FSTs. On the 

video, when asked whether she thought she was safe to 

drive, defendant responded, “Not right now. Fuck no.”

Defendant testified at her trial. She explained that 

she drank some beers at an Easter party at her sister’s 

house. Defendant denied driving the vehicle after drinking 

alcohol that day. Defendant stated that her husband drove 

the vehicle. After closing arguments and jury instructions, 

the jury returned a verdict of guilty on the charge of DUII. 

Defendant appeals.

On appeal, defendant raises two assignments of

error. First, she argues that the trial court improperly 

admitted the officer’s testimony that “five out of eight clues 

on the walk-and-turn test was consistent with being unsafe 

to drive, driving erratically, exhibiting mood swings, having 

an odor of alcohol and watery eyes, and was inconsistent 

with being sober.” Second, defendant argues that the trial 

court improperly admitted the officer’s testimony that “the 

FSTs were scientifically validated.”

The majority focuses on the second assignment of 

error. 325 Or App at 137. Defense counsel did not object 

to Miguel’s testimony that FSTs are “designed to determine impairment,” nationally “standardized,” and that “[t]

here have been studies conducted to prove their validity.” 

As a result, the majority conducts a plain-error review. Id.

Relying on State v. Eatinger, 298 Or App 630, 448 P3d 636 

(2019), and State v. Beltran-Chavez, 286 Or App 590, 400 

P3d 927 (2017), the majority determines that Miguel’s testimony was scientific evidence. 325 Or App at 138. Then, 

relying on State v. Reid, 312 Or App 540, 492 P3d 728 (2021), 

the majority concludes that the trial court had a duty to sua 

sponte exclude the testimony. 325 Or App at 139-40.

I respectfully disagree. “For an error to be plain 

error, it must be an error of law, obvious and not reasonably 

in dispute, and apparent on the record without requiring 

the court to choose among competing inferences.” State v. 

Vanornum, 354 Or 614, 629, 317 P3d 889 (2013). Here, it is 

not obvious that the officer’s statements about FSTs were 

scientific, and it is reasonable to dispute that contention. In 

Eatinger, 298 Or App at 642, we concluded that an officer’s 
148 State v. Ortiz

statements were scientific evidence because he “expressly

testified as to the scientific validation of the clues he had 

observed * **; he also expressly adopted the prosecutor’s 

statement that the FSTs were the product of scientific 

research.” (Emphasis in original; internal quotation marks 

omitted.)

But here, the testimony is less clear. Miguel’s statement that FSTs are “designed to determine impairment” 

does not appear to be scientific at all, and it is reasonable 

to construe it as a straightforward description of the purpose of FSTs. Miguel testified regarding the walk-and-turn 

test and the one-leg-stand test. In State v. O’Key, 321 Or 

285, 297, 899 P2d 663 (1995), the Supreme Court indicated 

that testimony regarding those two tests is not scientific 

because, unlike the horizontal gaze nystagmus test, they 

“obtain their legitimacy from effects of intoxication based 

on propositions of common knowledge.”

Admittedly, the officer’s statements that those two 

tests are nationally “standardized” and that “[t]here have 

been studies conducted to prove their validity” come closer 

to crossing the line between expert testimony based on 

training and experience and expert testimony that is scientific. But it is not obvious or beyond reasonable dispute that 

they do so. In Beltran-Chavez, 286 Or App at 616, we held 

that testimony that the defendant “passed” or “failed” the 

FSTs was scientific evidence that was inadmissible absent a 

sufficient foundation. “When an officer testifies that a defendant ‘failed’ the walk-and-turn test or the one-leg-stand test, 

that testimony relies on an external scoring rubric to prove 

that the defendant was objectively, measurably impaired. 

Indeed, the state acknowledged as much by arguing, in 

response to defendant’s pretrial motion, that FSTs are standardized tests.” Id. at 611. Similarly, in Reid, 312 Or App at 

543, the officer’s testimony was objectionable because the 

officer described the end result of the test as a pass or fail.

But here, unlike in Beltran-Chavez or Reid, the officer did not testify that defendant failed the two FSTs. Miguel 

did refer to the tests as nationally “standardized,” but, by 

itself, it is not clear that statement is scientific. Miguel’s use 

of the word “standardized” was likely something she learned 
Cite as 325 Or App 134 (2023) 149

in her training because she stated that her training course 

was called “Standardized Field Sobriety Tests.” Miguel also 

explained that “it’s a national standard, so it’s not just something that I made up or anybody in my department made up. 

It is a national standardized test. It is conducted the same 

way, it has the same set of instructions, same set of rules for 

each person that performs that nationwide.” So understood, 

“standardized” does not necessarily imply that the test is 

grounded in principles of science; instead, it could be understood to mean that the officer was trained to use a test for 

impairment that is the same test used by law enforcement 

throughout the United States. See Eatinger, 298 Or App at 

636 (referring to the “NHTSA’s ‘standardized field sobriety 

test curriculum’”).

Miguel’s reference to studies conducted to prove the 

validity of FSTs comes closer to expert testimony based on 

science, but, unlike the officer in Eatinger, Miguel did not 

refer to FSTs as “scientifically validated” or as “the product 

of scientific research.” 298 Or App at 642. Thus, it is less 

clear that the jury would have viewed Miguel’s testimony 

as drawing “its convincing force from some principle of science, mathematics and the like.” Id. at 640 (quotation marks 

omitted). The key point here is that “the line between expert 

testimony based on training and experience and expert 

testimony that is scientific can often be difficult to draw.” 

Id. at 641. The instant case is a good example of that difficulty. Because the error is not obvious, it is not plain. See

State v. Serrano, 355 Or 172, 182, 324 P3d 1274 (2014), cert 

den, 576 US 1037 (2015) (rejecting plain-error argument 

because “defendant has not demonstrated the obviousness 

of the posited unpreserved error”).

Even if the error was plain, we should not exercise 

our discretion to consider it. A decision to consider plain 

error should be made with the “utmost caution” because it 

undercuts the policies served by the preservation doctrine 

and OEC 103(1)(a). Ailes v. Portland Meadows, Inc., 312 Or 

376, 382, 823 P2d 956 (1991). “It is only in rare and exceptional cases that this court will notice an alleged error 

where no ruling has been sought from the trial judge.” State 

v. Gornick, 340 Or 160, 166, 130 P3d 780 (2006) (internal 

quotation marks omitted). The determination of whether to 
150 State v. Ortiz

exercise our discretion to address a plain error involves the 

consideration of a variety of factors, including “the competing interests of the parties; the nature of the case; the gravity of the error; the ends of justice in the particular case; 

how the error came to the court’s attention; and whether 

the policies behind the general rule requiring preservation 

of error have been served in the case in another way, i.e., 

whether the trial court was, in some manner, presented 

with both sides of the issue and given an opportunity to correct any error.” Ailes, 312 Or at 382 n 6.

The majority concludes that there was a plain error 

and it exercises its discretion to consider the error because 

it was not harmless. 325 Or App at 139-40. According to the 

majority, “Miguel’s testimony that the FSTs were scientifically validated ‘presented the jury with evidence that had 

persuasive value apart from [other evidence] that defendant 

was impaired.’” Id. at 140-41.

Respectfully, the majority downplays the significant 

evidence of defendant’s impairment. Miguel “could smell 

the odor of an alcoholic beverage” coming from defendant’s 

breath, and defendant had “watery eyes.” Defendant was emotional and had “cyclical mood cycles.” Defendant told Miguel 

that she was feeling a little bit tipsy, and she did not believe 

that she was safe to drive. The jury watched video from 

Miguel’s body camera, and, when Miguel asked defendant 

whether she thought she was safe to drive, she responded, 

“Not right now. Fuck no.” Defendant had five beers that day. 

When asked to rate her intoxication on a scale of one to 10, 

defendant rated herself as a four. Defendant told the officer 

that “she was not wearing underwear because she had previously urinated herself during the day.” The jury watched 

video of defendant’s performance on the walk-and-turn test 

and the one-leg-stand test. Having done so, the jurors could 

assess for themselves whether defendant exhibited signs of 

impairment.

Granted, “scientific evidence has manifest potential to influence a jury,” Eatinger, 298 Or App at 646, but 

here, it is not clear that the jury would have viewed Miguel’s 

challenged statements as scientific. The nature of the FSTs 

was not a central issue and, when compared to the ample 
Cite as 325 Or App 134 (2023) 151

evidence of impairment, there is little likelihood that the 

jury’s verdict was affected by Miguel’s reference to FSTs as 

“standardized” tests or by her statement regarding studies 

that prove their validity. Cf. Beltran-Chavez, 286 Or App at 

618 (The erroneous admission of testimony that the defendant failed the walk-and-turn test was not harmless because 

the other evidence that defendant was under the influence of 

alcohol “was not overwhelming.”). The unpreserved error, if 

any, was harmless, so we should not exercise our discretion 

to consider it. See State v. Kerne, 289 Or App 345, 349, 410 

P3d 369 (2017), rev den, 363 Or 119 (2018) (“One circumstance in which we will not and cannot exercise our discretion to correct a plain error is when the error is harmless, 

that is, when there is little likelihood that the error affected 

the jury’s verdict.”).

There is another, perhaps more important, reason

why we should not exercise our discretion to engage in 

plain-error review. By doing so, the majority creates a new 

rule requiring trial judges to sua sponte strike testimony 

regarding FSTs that may or may not be scientific.1 For the 

majority, that new rule arises as a “necessary implication 

from Reid.” 325 Or App at 139-40. But in Reid, relying on 

Beltran-Chavez, we determined that it was plain error for 

an officer to testify regarding passing or failing an FST, a 

point conceded by the state. Reid, 312 Or App at 543-44. 

In Reid, we made no statement concerning whether it was 

plain error for the trial court to fail to sua sponte exclude the 

testimony. If such a duty arises as a necessary implication 

from Reid, then we should be especially careful not to invoke 

1 Other state courts are more cautious about requiring a judge to intervene beyond unequivocal vouching. See, e.g., State v. Hanes, 171 NH 173, 182, 

192 A3d 952, 959 (2018) (“We have never held that a trial court must sua sponte 

strike or issue a curative instruction with respect to witness testimony and, in 

fact, we have suggested that courts should refrain from taking such action.” 

(Underscoring in original; internal quotation marks omitted.)); Com v. Pimental, 

54 Mass App Ct 325, 330, 764 NE 2d 940 (2002) (“[T]he trial judge’s responsibility to conduct a fair trial does not require her to act as an attorney for a pro se 

litigant. Certainly, a defendant represented by counsel is entitled to no greater 

process.”); State v. Wragg, 61 Conn App 394, 399, 764 A2d 216, 220 (2001) (“When 

subsequent events reveal that [counsel’s strategic choice not to object] *** was 

an imprudent choice, however, the defendant is not entitled to turn the clock back 

and have [the appellate court] reverse the judgment because the trial court did 

not, sua sponte, strike the testimony and give the jury a cautionary instruction.” 

(Internal quotation marks omitted.)).
152 State v. Ortiz

the plain-error doctrine when the claimed evidentiary error 

is a close call and not obvious.

There is a significant difference between the question of whether testimony is inadmissible and whether a 

trial judge plainly errs by failing to sua sponte exclude or 

strike the testimony. See State v. Corkill, 262 Or App 543, 

551, 325 P3d 796, rev den, 355 Or 751 (2014) (“[T]he question before us *** is not whether the prosecutor’s crossexamination of defendant was objectionable. Rather, the 

pertinent question is whether the trial court plainly erred 

by not interrupting the prosecutor’s cross-examination of 

defendant sua sponte.”). The very act of sua sponte intervening to either strike testimony or give a curative instruction 

is wrought with peril. As one federal judge has cogently 

explained regarding the practical effects of requiring judges 

to sua sponte intervene during trial:

“A conclusion that the admission of certain evidence constitutes plain error is a determination that the evidence 

was so obviously inadmissible and prejudicial that, despite 

defense counsel’s failure to object, the district court, sua 

sponte, should have excluded the evidence. Thus, the existence of plain error review forces the district court, in an 

effort to avoid the reversal of conviction and a retrial, to 

intervene and exclude the evidence on its own initiative. In 

determining whether to do so, the district court must either 

ignore the possibility that defense counsel is choosing not 

to object for strategic reasons (and therefore intervene in 

every instance) or must weigh that possibility against the 

potential time and cost of a retrial (assuming one is even 

possible under the circumstances). To the extent the district court even attempts the latter analysis, however, it 

does so at a specific moment during the course of the trial 

without the benefit of the entire record (in particular, what 

other evidence the prosecution is prepared to offer, and 

what use the prosecution or defense intends to make of 

the evidence). Because it is extraordinarily difficult, if not 

impossible, to determine, mid-trial, whether the admission 

of a certain piece of excludable evidence prejudices a defendant’s substantial rights, the possibility of a retrial creates 

an incentive for the district court always to intervene. This 

result essentially deprives defense counsel of the ability to 

determine strategically a client’s most effective defense—a 

consequence I would prefer to avoid.”
Cite as 325 Or App 134 (2023) 153

United States v. Smith, 459 F3d 1276, 1300-01 (11th Cir 

2006) (Tjoflat, J., concurring) (emphasis in original; footnote 

omitted).

When a witness, expert or otherwise, is asked 

to comment upon the credibility of another witness, the 

Supreme Court has instructed trial judges to sua sponte “cut 

off the inquiry before a jury is contaminated by it.” State v. 

Milbradt, 305 Or 621, 630, 756 P2d 620 (1988); see B.A. v. 

Webb, 253 Or App 1, 12, 289 P3d 300 (2012), rev den, 353 Or 

428 (2013) (“It is legally impermissible under Oregon law for 

a witness to comment on the credibility of another witness, 

and, in enforcing that principle, trial courts are obligated, 

sua sponte, to exclude and, if necessary, strike testimony 

that comments on a witness’s credibility.”); see also State v. 

Chandler, 360 Or 323, 330-31, 380 P3d 932 (2016) (discussing history of the “judicially created rule” against vouching). 

Such evidence is so obviously contrary to the fundamental 

structure of our adversarial system that sua sponte intervention is rightfully considered a part of the basic functions 

of a trial judge. See Davis v. Cain, 304 Or App 356, 363, 

467 P3d 816 (2020) (“Because credibility determinations are 

the exclusive province of the jury, witnesses are categorically prohibited from expressing a view on whether another 

witness is ‘telling the truth.’” (Quoting State v. Middleton, 

294 Or 427, 438, 657 P2d 1215 (1983).)). Now the majority 

imposes a similar duty on trial judges whenever it appears 

that a police officer may be about to testify regarding the 

purpose of FSTs, that they are “standardized” tests, or why 

law enforcement uses them. The basic, weighty concerns of 

vouching and the functions of a jury are not at play here, 

so we should not create a new rule requiring a sua sponte

intervention.

Indeed, even in vouching cases, we tend to apply the 

rule sparingly. See Davis, 304 Or App at 368 (“[A]t least with 

respect to ‘true’ vouching, a trial court may commit plain 

error if it fails to sua sponte address vouching by a witness,” 

but, “[t]o date, we have not reversed a conviction on direct 

appeal on the basis that a trial court plainly erred in failing, 

sua sponte, to address vouching by a prosecutor.”). In vouching cases, “if a witness’s testimony was ambiguous—such 

that the witness may or may not have been vouching—there 
154 State v. Ortiz

is no plain error in not having stricken the testimony sua 

sponte, in part because the lack of objection prevented clarification of the testimony.” State v. Murphy, 319 Or App 

330, 335, 510 P3d 269 (2022). In addition, even if there was 

unambiguous vouching that a trial court failed to strike sua 

sponte, we have declined to exercise our discretion to correct the error if it was not grave and had little likelihood of 

affecting the outcome. Id. at 338-40. Here, for the reasons 

explained above, the officer’s challenged testimony may or 

may not have been scientific, but it was not clearly so. As a 

result, there was no plain error when the trial judge failed 

to sua sponte intervene. In addition, even if the officer’s brief 

statements about why FSTs are used could be construed as 

scientific, we should not exercise our discretion to consider 

the error because there is little likelihood that the officer’s 

statements affected the jury’s verdict.

In vouching cases, we also consider “whether there 

is a plausible tactical reason why defense counsel forewent 

a motion to strike.” State v. Ramirez-Estrada, 260 Or App 

312, 320, 317 P3d 322 (2013), rev den, 355 Or 317 (2014). 

Here, there is a plausible reason. Although defense counsel argued that the state could not meet its burden to show 

that defendant was impaired, defense counsel’s other theory of the case was that the state could not prove beyond 

a reasonable doubt that she drove the vehicle. Before trial, 

defense counsel objected to any testimony from the witness 

who made the 9-1-1 call that would involve that witness 

making an in-court identification of defendant as the person 

who drove the vehicle. The state agreed that only the police 

officer, who did not see defendant driving, would make an 

in-court identification of defendant.

In his opening statement, defense counsel argued 

that the “two basic issues” in the case were whether defendant was driving and whether she was under the influence 

of alcohol to an extent that she could not operate a vehicle 

safely. He argued that “there is not one witness who is going 

to be able to identify [defendant] as driving the vehicle.” 

Defense counsel pointed out that the police were initially 

responding to a report of domestic violence or harassment, 

but “they quickly put that aside and figured, you know, let’s 
Cite as 325 Or App 134 (2023) 155

go after [defendant] for driving with alcohol, despite not 

having enough evidence that she was even driving the vehicle at all.”

Based on that theory of the case, it is plausible that 

defense counsel did not want to draw more attention to the 

officer’s testimony regarding FSTs, their purposes, whether 

they are nationally standardized, or their validity. Had 

counsel objected, there was a risk that the state would either 

establish the foundation with further testimony by Miguel, 

or, potentially more damaging, provide another witness that 

could buttress the officer’s testimony with scientific underpinnings and foundation. In vouching cases, when there is a 

plausible explanation for defense counsel’s failure to object, 

then it is not plain error for a trial court to fail to intervene 

sua sponte. See State v. Vage, 278 Or App 771, 777, 379 P3d 

645, rev den, 360 Or 697 (2016) (“It is well established that 

an error does not qualify as plain error if the record contains 

a competing inference that the party may have had a strategic purpose for not objecting, and that competing inference 

is plausible.” (Internal quotation marks omitted.)). The same 

reasoning applies here. We should not engage in plain-error 

review of defendant’s second assignment of error.

I briefly address the first assignment of error. Defendant assigns error to the trial court’s ruling permitting 

Miguel to compare defendant’s performance on the walkand-turn test to what Miguel would expect from a sober person. The trial court did not err by admitting the testimony. 

“[C]ertain officers may be practical experts in recognizing 

intoxication, and, when they are, they may offer expert opinions on that topic without first showing that the process by 

which they arrived at their opinions is scientifically valid, 

provided that their testimony does not imply that it is based 

on science.” Beltran-Chavez, 286 Or App at 604. “Specialized 

expert opinion evidence based on a witness’s training and 

experience draws its force from that training and experience, but not necessarily from the mantle of science.” State 

v. Rambo, 250 Or App 186, 195, 279 P3d 361 (2012), rev den, 

353 Or 447 (2013). Here, Miguel testified regarding her 

training and experience administering the walk-and-turn 

test. That testimony was sufficient to qualify Miguel to offer 
156 State v. Ortiz

an opinion comparing defendant’s performance on the test 

to what she would expect from a sober person. Accordingly, 

I would affirm the judgment of conviction.

Respectfully, I dissent.