Del Cid: Concurring Opinion Signals No Per Se Admissibility of CSAAS‑Type Testimony Under MRE 702

Introduction

In People of the State of Michigan v. Juan Jose Del Cid, the Michigan Supreme Court denied the defendant’s application for leave to appeal from an order of the Michigan Court of Appeals. Although the Court issued no merits ruling, Justice Thomas authored a concurrence that squarely identifies unresolved and important questions about the admissibility of expert testimony on the “typical” behaviors of child sexual abuse victims—particularly testimony often associated with the so-called Child Sexual Abuse Accommodation Syndrome (CSAAS).

The case arises from a criminal prosecution in Ottawa County, where the prosecution sought to call Barbara Welke as an expert to testify about delayed disclosure and the disclosure process in child sexual abuse cases. The defense moved in limine to exclude the testimony and argued that the trial court erred by not holding a Daubert hearing under Michigan Rule of Evidence (MRE) 702. The trial court denied the motion and, according to the record before the Supreme Court, limited Welke’s testimony to disclosure-related behavior. The Supreme Court declined to review, but the concurrence uses the occasion to caution lower courts against treating such expert testimony as per se admissible without a reliability assessment, and to invite a future case presenting a fuller record for review.

The central legal issue flagged by the concurrence is whether, under Michigan’s current Daubert-based framework for expert evidence (MRE 702), expert testimony about common victim behaviors—including delayed disclosure—may be admitted without a reliability inquiry, as some readings of People v. Peterson (1995) and subsequent Court of Appeals decisions suggest. The concurrence stresses that MRE 702 imposes two independent requirements—helpfulness and reliability—and that both must be satisfied.

Summary of the Opinion

The Michigan Supreme Court denied leave to appeal, stating it was not persuaded that the questions presented warranted review. Justice Thomas concurred in the denial but wrote separately to highlight unresolved tensions in Michigan law regarding expert testimony about victim behavior in child sexual abuse cases:

The concurrence reiterates that under MRE 702, expert testimony must independently satisfy two elements: (1) it must assist the trier of fact on a matter beyond common knowledge; and (2) it must be reliable—based on sufficient facts/data, reliable principles/methods, and a reliable application to the case.
It questions any interpretation of Peterson, or Court of Appeals decisions in Spaulding and Muniz, as authorizing per se admissibility of behavior‑pattern testimony without a reliability analysis under the post-Daubert version of MRE 702.
Drawing on People v. Kowalski, the concurrence explains that even when a topic (e.g., false confessions or counterintuitive victim behavior) is beyond common knowledge and may help a jury, gatekeeping for reliability remains essential.
The concurrence acknowledges that other jurisdictions and segments of the scientific community have criticized aspects of CSAAS evidence, underscoring the need for record development and reliability review.
The concurrence indicates that this case is not a suitable vehicle to resolve these issues due to a limited record and because the defense apparently did not request a Daubert hearing; it invites the right case for future review.

Detailed Analysis

Precedents and Authorities Cited

The concurrence situates its analysis within Michigan and federal precedent governing expert testimony:

People v. Peterson (1995): Peterson permits, with important limitations, expert testimony about “typical and relevant symptoms” of child sexual abuse to explain behavior that jurors might wrongly view as inconsistent with abuse, and to rebut attacks on credibility by drawing consistencies between a victim’s behavior and that of other victims. At the same time, Peterson imposes strict prohibitions: the expert cannot testify that abuse occurred, cannot vouch for the victim’s veracity, and cannot opine on the defendant’s guilt. Critically, Peterson—decided under the now-superseded Davis/Frye framework—stated that the Davis/Frye general-acceptance test did not apply to such behavioral-science testimony.
People v. Beckley (1990): Beckley provided the foundational view (adopted by a majority across separate opinions) that the Davis/Frye test does not govern behavioral-science evidence, a view on which Peterson later relied.
Gilbert v. DaimlerChrysler Corp. (2004), adopting Daubert in Michigan: Gilbert replaced Davis/Frye with the Daubert reliability framework, as now codified in MRE 702. Under this regime, trial courts must act as gatekeepers to ensure expert testimony is not only relevant but reliable.
Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) and Kumho Tire Co. v. Carmichael (1999): Daubert requires trial judges to screen expert testimony for relevance and reliability; Kumho Tire confirms that Daubert applies to all forms of expert knowledge—scientific, technical, and other specialized—expressly capturing behavioral-science testimony.
People v. Kowalski (2012): Applying Daubert-era MRE 702, the Court held that expert testimony on false confessions can meet the “assist the trier of fact” threshold because false confessions run contrary to common sense, but still may be excluded if the proponent cannot show reliability. Kowalski exemplifies the two distinct and independent MRE 702 inquiries.
People v. Spaulding (2020, COA) and People v. Muniz (2022, COA): These decisions, relying on Peterson, suggested that expert testimony explaining counterintuitive behavior of trauma victims is admissible without a scientific reliability analysis. The Del Cid concurrence expressly questions that proposition under today’s MRE 702.
People v. Tomasik (2015): While the Supreme Court ultimately granted a new trial on a different ground, its order specified that if expert testimony were to be offered on retrial, the trial court must conduct a Daubert hearing. Tomasik thus foreshadows the present concern with reliability gatekeeping for this class of expert evidence.
People v. Warner (2024): Cited for the definition of a Daubert hearing as the trial court’s gatekeeping process to ensure reliability under MRE 702.
People v. Jackson (2024) (dissent) and People v. Mejia (2020) (dissent): Cited to show that members of the Michigan Supreme Court have previously expressed concern about the scientific foundation and admissibility of CSAAS-based testimony.

Legal Reasoning in the Concurrence

The concurrence’s legal analysis turns on the structure and demands of MRE 702 as it exists in the Daubert era:

Two independent requirements under MRE 702: The proponent must show both that the testimony will assist the trier of fact (i.e., addresses a matter beyond the ken of common knowledge) and that it is reliable (sufficient facts/data, reliable principles/methods, reliable application). These are “separate and distinct and must each be satisfied independently.”
“Beyond the ken” does not end the inquiry: While testimony about delayed disclosure or other counterintuitive behaviors may clear the threshold helpfulness hurdle (as Kowalski teaches for false confessions), that does not absolve the proponent from establishing reliability. Reliability is a distinct requirement that must be established affirmatively, often through a Daubert hearing when contested or where the basis of the testimony is not apparent from the record.
Peterson’s Davis/Frye context has changed: Peterson expressly declined to apply the Davis/Frye test to behavioral evidence. But since Gilbert and the amendments to MRE 702, Michigan has adopted Daubert’s gatekeeping, which applies to all expert testimony—including behavioral-science testimony. The concurrence indicates that Peterson should not be read to displace or diminish Daubert-era reliability screening for victim-behavior testimony.
Concern with per se admissibility: The concurrence flags language in Spaulding and Muniz suggesting no need for a reliability analysis. It warns that treating such testimony as categorically admissible would be inconsistent with MRE 702’s text and Daubert/Kumho Tire’s mandate that courts assess reliability for all expert testimony.
Record development is essential: The concurrence notes both scientific debate about CSAAS and divergent approaches in other jurisdictions. Without adequate lower-court records—built through proper motions and, where appropriate, Daubert hearings—Michigan courts cannot meaningfully assess the reliability of particular forms of disclosure-behavior testimony.
This case is not the vehicle: The record indicates the expert testimony would be limited to delayed disclosure and the disclosure process; the defense apparently did not request a Daubert hearing; and the basis and scope of the proposed testimony are not well developed in the materials before the Court. Accordingly, the concurrence agrees denial is appropriate but encourages resolution in a future case.

What This Means for the Law Going Forward

While the order denying leave creates no new binding precedent, the concurrence is a significant signal about how the Supreme Court views expert testimony on victim behavior in child sexual abuse cases under MRE 702:

No per se admissibility: Courts should not assume that testimony explaining “typical” behaviors of child sexual abuse victims—such as delayed disclosure—is automatically admissible. Even if helpfulness is established, reliability still must be shown under MRE 702.
Gatekeeping applies to behavioral-science experts: Following Daubert and Kumho Tire, behavioral and social-science expertise falls within the court’s gatekeeping obligation. Trial judges should be prepared to hold Daubert hearings where the reliability of such testimony is challenged or unclear.
Peterson remains but must be harmonized with MRE 702: Peterson’s substantive limits (no “abuse occurred,” no vouching, no guilt opinion) continue to constrain how experts may testify. But Peterson’s Davis/Frye-era assumption that behavioral evidence escapes general-acceptance testing cannot be read to exempt such evidence from today’s reliability screening under MRE 702.
Litigation practice will likely adjust: Prosecutors offering disclosure-behavior experts should be ready to proffer the empirical bases, methodologies, and application to the case facts. Defense counsel should timely request Daubert hearings and develop records contesting reliability—especially when testimony is derivative of CSAAS or similar constructs that have drawn scientific criticism.

Complex Concepts Simplified

MRE 702 (Michigan’s expert-evidence rule): Allows expert testimony if it will assist the jury and if it is reliable. Reliability requires (a) sufficient facts/data; (b) reliable principles/methods; and (c) a reliable application of those principles/methods to the case facts.
Daubert hearing: A pretrial proceeding where the judge, as gatekeeper, examines whether the expert’s methods are reliable and properly applied. This is not a mini-trial of the case but a focused inquiry into the expert’s foundation.
“Beyond the ken of common knowledge”: A threshold concept meaning the expert’s topic is something jurors are unlikely to know from everyday experience (e.g., counterintuitive disclosure behavior by abuse victims, or the phenomenon of false confessions).
CSAAS (Child Sexual Abuse Accommodation Syndrome): A descriptive framework proposed in the 1980s identifying common patterns in child sexual abuse victims—such as secrecy, helplessness, accommodation, delayed and conflicted disclosure, and recantation. It has been criticized for limited empirical validation and for potential misuse as de facto vouching.
Per se admissibility vs. case‑by‑case admissibility: Per se admissibility treats a category of evidence as automatically admissible; Daubert-era MRE 702 rejects that approach for expert testimony, requiring case-specific reliability showings.
Vouching: An expert may not tell the jury that the victim is telling the truth, that abuse occurred, or that the defendant is guilty. Peterson expressly prohibits such testimony.
Motion in limine: A pretrial motion to admit or exclude evidence. Parties should use this mechanism to request a Daubert hearing when expert reliability is at issue.

Practical Implications and Guidance

For trial judges: When a party proffers expert testimony about victim behaviors such as delayed disclosure, consider whether a Daubert hearing is necessary to assess reliability. The court should make findings that reflect both halves of MRE 702—helpfulness and reliability—and enforce Peterson’s prohibitions against vouching and direct guilt opinions.
For prosecutors: Do not rely on Peterson alone. Be prepared to demonstrate reliability with literature, data, and clearly articulated principles/methods, and to explain the expert’s limited, non‑vouching role (e.g., educating the jury about counterintuitive behaviors without implying this victim was abused).
For defense counsel: Preserve the issue. File a motion in limine expressly requesting a Daubert hearing, identify the precise opinions to be excluded, and develop the record (cross‑examination on methods, literature, error rates, standards, and application to the case). Consider MRE 403 arguments if the risk of unfair prejudice or juror confusion substantially outweighs probative value.
For appellate practitioners: Build a record below. The concurrence underscores that without a developed record on an expert’s methodology and application, appellate courts will be hamstrung in reviewing reliability and admissibility determinations.

How This Opinion Fits Within the Broader Doctrinal Landscape

The Del Cid concurrence reflects a broader national reassessment of CSAAS‑type testimony. Post‑Kumho Tire, jurisdictions increasingly require trial courts to apply reliability screening to behavioral-science testimony, and some have curtailed or redefined the permissible scope of CSAAS-based evidence. Michigan law has for decades permitted limited educational testimony about counterintuitive victim behavior, but the reliability demands of modern MRE 702—and the concern over subtle vouching—press for careful, case-specific gatekeeping.

Within Michigan, Tomasik’s direction to conduct Daubert hearings when expert testimony is sought, Kowalski’s clear two‑step MRE 702 framework, and the present concurrence all point to the same theme: expertise on topics beyond common knowledge can be helpful, but only reliable expert testimony, tightly constrained to avoid vouching or guilt opinions, should reach the jury.

Conclusion

The Supreme Court’s denial of leave in Del Cid sets no new binding precedent. Yet Justice Thomas’s concurrence meaningfully clarifies the direction of Michigan law. It cautions that expert testimony on the “typical” behaviors of child sexual abuse victims—including delayed disclosure—cannot be treated as per se admissible under Peterson without a reliability analysis under the Daubert‑based MRE 702. The concurrence harmonizes Peterson’s substantive limits with modern gatekeeping obligations and highlights scientific and judicial skepticism about CSAAS‑derived opinions.

Key takeaways:

MRE 702 imposes two independent requirements—helpfulness and reliability—and both must be satisfied for expert testimony on victim behavior.
Trial courts should be prepared to hold Daubert hearings when such testimony is proffered or challenged, and should make findings addressing the reliability components of MRE 702.
Experts may educate jurors about counterintuitive behaviors but may not testify that abuse occurred, vouch for the victim’s credibility, or opine that the defendant is guilty.
A future case with a well‑developed record is needed for the Supreme Court to definitively reconcile Peterson with the Daubert era and to address the admissibility of CSAAS‑type testimony in Michigan.

In sum, Del Cid does not change the law today, but it plainly signals that Michigan’s high court expects rigorous, case‑specific reliability gatekeeping for behavioral‑science expert testimony under MRE 702.