State v. Dacey, 491 P.3d 1205

Background

Early-morning welfare check found Dacey asleep behind the wheel; field sobriety tests mixed and breath alcohol = 0; later blood test detected methamphetamine/amphetamines.
Officer Jessica Raddatz, a certified Drug Recognition Evaluator (DRE), performed a DRE at the jail and concluded Dacey was impaired by a stimulant "downside" despite many normal vital signs.
The State listed Raddatz as a lay witness and did not disclose her as an expert under I.C.R. 16(b)(7); Dacey requested expert disclosure and voir dire pretrial.
Magistrate allowed Raddatz to testify as a lay witness about "downside" effects and denied voir dire; jury convicted Dacey of DUI with a prior enhancement.
District court (intermediate appeal) affirmed; Idaho Supreme Court reversed, held Raddatz’s "downside" testimony was expert testimony requiring disclosure under I.C.R. 16(b)(7), and found the nondisclosure was not harmless — vacating the conviction and remanding.

Issues

Issue	State's Argument	Dacey's Argument	Held
Whether Raddatz's "downside" testimony was expert testimony requiring I.C.R. 16(b)(7) disclosure	Testimony was lay: based on observations, DRE procedures, and cross-examination could expose weaknesses	Testimony relied on specialized training, interpretation beyond DRE manual and common sense, so qualifies as expert under I.R.E. 702	Court: Testimony was expert under I.R.E. 702; State should have disclosed her as an expert; admitting it without disclosure was an abuse of discretion
Whether denying voir dire in aid of Dacey's objection was error	Voir dire not necessary because testimony was lay and could be tested via cross-examination	Denial prevented meaningful probing of qualifications, methodology, and basis for expert opinions	Court did not resolve as a separate reversible error but noted voir dire would likely have avoided the issue and that denial was prejudicial in context
Whether trial court applied the correct Rule 702 analysis before admitting testimony	Magistrate properly treated testimony as lay under I.R.E. 701	Magistrate should have assessed qualifications and whether testimony would assist the trier of fact under I.R.E. 702	Court: Magistrate failed to apply proper expert-admissibility analysis; testimony functioned as expert opinion under Rule 702
Whether the nondisclosure/admission error was harmless	Error was harmless because other evidence (field tests, blood results, video) supported guilt	Nondisclosure was prejudicial; State heavily relied on Raddatz in closing and denial foreclosed effective pretrial preparation/rebuttal	Court: Error was not harmless under Yates/Garcia framework; State failed to show harmlessness beyond a reasonable doubt; conviction vacated

Key Cases Cited

State v. Hall, 163 Idaho 744, 419 P.3d 1042 (2018) (distinguishing lay investigative description from expert opinion)
State v. Morin, 158 Idaho 622, 349 P.3d 1213 (Ct. App. 2015) (expert disclosure required where expert opined on intoxication and basis was not disclosed)
State v. Caliz-Bautista, 162 Idaho 833, 405 P.3d 618 (2017) (expert admissibility requires qualification and helpfulness)
State v. Garcia, 166 Idaho 661, 462 P.3d 1125 (2020) (harmless-error Yates two-part test; compare probative force of record excluding the error)
Bailey v. Bailey, 153 Idaho 526, 284 P.3d 970 (2012) (standard of review for Supreme Court when district court sits in intermediate appellate capacity)
State v. Youmans, 161 Idaho 4, 383 P.3d 142 (Ct. App. 2016) (officer’s use of nontechnical database and resulting identification treated as lay testimony)