State v. Thomas, 279 Or. App. 98

Defendant convicted of four counts of first-degree sodomy and four counts of first-degree sexual abuse for molestation of nephew ZM over several years; convictions affirmed on appeal.
Defense theory: ZM’s memory was false/implanted due to parental bias (father Marin) and investigative bias by Amani Center in favor of mother (Crosby).
Defense proffered two expert witnesses: Dr. Daniel Reisberg (psychology professor on traumatic memory) and Dr. Wendy Bourg (clinical psychologist reviewing the Amani Center interview).
Reisberg sought to describe details from VCUG medical-memory studies (children’s memory for invasive genital exams) to support his opinions about traumatic memory. Trial court excluded those study details as hearsay but allowed general testimony about trauma enhancing memory.
Bourg would have testified that the Amani interviewer failed to follow up on ZM’s improbable statements (e.g., teeth knocked out and regrown; allegations of physical abuse), suggesting potential interviewer bias. The court limited Bourg’s testimony because the interviewer, Lindquist, had already admitted those facts on cross-examination.
The court affirmed both exclusions on appeal: Reisberg’s study details were inadmissible hearsay not necessary to explain his expert opinion; Bourg’s extrinsic evidence was barred because the witness had fully admitted the bias-related facts.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Admissibility of VCUG study details relied on by expert under OEC 703	State: study details are hearsay and not admissible to prove truth; expert can rely on studies but cannot present their detailed contents to jury.	Defendant: OEC 703 permits an expert to base opinion on otherwise inadmissible data and jury should see study details to assess expert foundation (analogizing to McCathern).	Exclusion affirmed — details were hearsay and were not necessary to explain or support an expert opinion actually offered; expert could testify generally about traumatic memory.
Admission of second expert’s testimony about interviewer bias	State: Bourg’s testimony duplicative; Lindquist already admitted lack of follow-up on cross.	Defendant: Bourg’s critique of the interview was relevant to show Amani Center bias favoring the mother and to impeach interviewer credibility.	Exclusion affirmed — under OEC 609-1(2) extrinsic evidence inadmissible when the witness fully admits the facts showing bias; Lindquist had admitted those facts.

McCathern v. Toyota Motor Corp., 332 Or. 59 (expert may recount out-of-court incident details to explain expert reasoning when offered only to show foundation and not for truth)
Oberg v. Honda Motor Co., 316 Or. 263 (limited-purpose admission of documents not hearsay when offered to show notice rather than truth)
Hubbard v. 297 Or. 789 (extrinsic impeachment evidence inadmissible when witness fully admits bias-related facts)