THE CRITERIA FOR ALLOWING EXPERT TESTIMONY ON WITNESS-IDENTIFICATION OF A DEFENDANT CLARIFIED; WHETHER TO ALLOW SUCH EVIDENCE DOES NOT TURN ON THE EXISTENCE OR THE STRENGTH OF CORROBORATING EVIDENCE; HERE EXPERT TESTIMONY ON CROSS-RACIAL IDENTIFICATION WAS PROPERLY ALLOWED (CT APP). ​

The Court of Appeals, in a full-fledged opinion by Judge Troutman, over an extensive dissent, affirming defendant’s conviction, clarified the criteria for admitting expert testimony on witness identification of a defendant. Here limited expert testimony was allowed on cross-racial identification:

Questions of the admissibility and scope of expert testimony concerning the factors that affect the reliability of eyewitness identifications in a particular case are addressed to the trial court’s sound discretion … . Courts deciding those questions apply traditional evidentiary principles … , which require the courts to weigh the testimony’s probative value against its prospect of causing undue prejudice to the opposing party, confusing the issues, misleading the jury, or unduly delaying trial … .

On an application to admit expert testimony of this sort, the trial court may need to determine whether the expert testimony is beyond the ken of the average juror or generally accepted in the scientific community … . Indeed, in Abney, we reversed and ordered a new trial where the trial court abused its discretion in denying an application to present expert testimony on several factors, concluding that the court should have held a Frye hearing to resolve the issue of general acceptance … . While general acceptance may be established at a Frye hearing, a hearing is not necessary in all cases … . General acceptance may be established through legal precedent … . Where the defendant fails to demonstrate that a topic of the proffered expert testimony is generally accepted in the relevant scientific community, the trial court should exclude or limit the testimony as appropriate … .

Courts must not decide whether evidence is admissible based solely on the existence or strength of corroborating evidence … . Nor should courts require adequate corroborating evidence as a prerequisite to weighing other considerations pertinent to admissibility … . Rather, courts should be guided by “whether the proffered expert testimony ‘would aid a lay jury in reaching a verdict’ ” … . People v Vaughn, 2024 NY Slip Op 05874, CtApp 111-26-24

Practice Point: Whether to allow expert testimony on witness-identification of a defendant does not turn on the existence or strength of corroborating evidence.