People v. Ramos, 388 P.3d 888

In November 2006 Ramos allegedly assaulted R.L. in a car; Ramos had a bleeding, bandaged hand and blood appeared on the victim’s jacket and hat. Ramos claimed the blood resulted from waving his hand (cast-off), not from striking the victim (transfer).
At trial a police detective viewed photographs and testified that some stains were transfer (physical contact) and others were cast-off/spatter; the trial court admitted that testimony as lay opinion under CRE 701.
The jury convicted Ramos of assault and a bias-motivated crime; the court of appeals reversed, holding the trial court abused its discretion by admitting the detective’s blood-pattern testimony as lay opinion.
The People appealed to the Colorado Supreme Court, which granted certiorari to resolve whether an ordinary person can reliably distinguish cast-off from transfer and thus whether the detective’s testimony required qualification as expert testimony under CRE 702.
The Colorado Supreme Court applied the Venalonzo test and held an ordinary person would not be able to reliably differentiate cast-off from transfer; the detective’s testimony relied on specialized experience and terminology and therefore should have been offered through an expert.

Issue	Plaintiff's Argument (People)	Defendant's Argument (Ramos)	Held
Whether a police detective’s testimony identifying blood as transfer (vs cast-off/spatter) may be admitted as lay opinion under CRE 701 or required expert qualification under CRE 702	Detective’s limited testimony was rooted in ordinary experience and perception and did not depend on specialized training; thus admissible as lay opinion	Differentiating cast-off vs transfer requires specialized experience and training; the detective’s conclusions exceeded ordinary knowledge and required expert qualification	The Court held the opinions on blood transfer vs cast-off went beyond ordinary experience and required expert qualification; admitting them as lay testimony was an abuse of discretion

Venalonzo v. People, 388 P.3d 868 (Colo. 2017) (announcing test distinguishing lay from expert opinion based on whether ordinary experience suffices)
People v. Ramos, 272 P.3d 1179 (Colo. App. 2012) (court of appeals reversed trial conviction because lay admission of blood-pattern testimony was improper)
People v. Stewart, 55 P.3d 107 (Colo. 2002) (standard for abuse of discretion review of evidentiary rulings)
People v. Rincon, 140 P.3d 976 (Colo. App. 2005) (discussing expectations about ordinary citizens’ knowledge for lay opinion)
United States v. McDonald, 933 F.2d 1519 (10th Cir. 1991) (factors for assessing whether testimony rests on ordinary, lay experience)