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People v. Coons.

2021 CO 70. No. 19SC485.  Admissibility of Expert Testimony—CRE 702—Relevance—Helpfulness to the Jury—“Fit”—Generalized Expert Testimony—Sufficient Logical Connection to the Facts to be Helpful to the Jury—CRE 403 Admissibility—Domestic Violence Expert Testimony—Power and Control Dynamic—Power and Control Wheel.

September 27, 2021


Before expert testimony is admitted into evidence, a trial court must find that it would be helpful to the jury. Whether expert testimony is helpful to the jury hinges on “fit”—the expert testimony must fit the case. Here, the Supreme Court considered how close a fit is required.

The Court held that generalized expert testimony fits a case if it has a sufficient logical connection to the factual issues to be helpful to the jury while still clearing the ever-present CRE 403 admissibility bar. In evaluating the fit of generalized expert testimony, a trial court must be mindful of the purposes for which such testimony is offered—that is, the reasons why the proponent of the evidence has asked the expert to educate the jury about certain concepts or principles.

Here, the trial court admitted the generalized expert testimony offered by the People on the dynamics of domestic violence, ruling that it would be helpful to the jury and impliedly finding that it passed muster under CRE 403. A jury then returned guilty verdicts against the defendant. But a Court of Appeals’ division of the reversed the judgment of conviction, concluding that some of the People’s generalized expert testimony did not fit the case. According to the division, the trial court’s failure to exclude those portions of the expert testimony that had no logical relation to the case facts constituted an abuse of discretion warranting reversal.

However, as the Supreme Court explained in Cooper, 2021 CO 69, __ P.3d __, while generalized expert testimony must fit the case, the fit need not be perfect; each aspect of such testimony need not match a factual issue. Because generalized expert testimony, by definition, seeks to inform the jury about generic concepts or principles without knowledge of the facts, it is almost inevitable that parts of such testimony will not be logically connected to the case. For that reason, the fit inquiry must be flexible. A trial court should not be expected to parse the proposed testimony and determine whether each statement the expert intends to utter is logically connected to a fact in the case. If the generalized expert testimony’s logical connection to the factual issues is sufficient to be helpful to the jury without running afoul of CRE 403, the testimony fits the case.

Still, attorneys and trial courts should do their best to avoid introducing generalized expert testimony that has no logical connection to the case facts. As relevant here, prosecutors should take care to endorse generalized expert testimony about domestic violence only in appropriate cases; and, when they do so, they should endeavor to present only testimony that is logically connected to the factual issues. Trial courts, in turn, should exercise their discretion in deciding whether to permit all, some, or none of the proffered testimony under the fit standard the Court articulated today. In doing so, trial courts should consider the feasibility and propriety of admitting only a portion of the proposed generalized expert testimony on a particular subject.

Because the division employed a fit standard that’s inflexible and overly exacting, and because the trial court’s decision to admit the challenged evidence was entitled to deference, the division erred. Applying the correct fit standard and affording the trial court’s decision its due deference, the Court concluded that the admission of the generalized expert testimony in question did not constitute an abuse of discretion. The Court therefore reversed the division’s judgment and remanded the case for further proceedings consistent with this opinion.

Official Colorado Supreme Court proceedings can be found at the Colorado Supreme Court website.

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