In United States v. Cristerna-Gonzalez, the Tenth Circuit clarified the law governing “expert” testimony by the police.
First, the Court clarified the boundary between “Opinion Testimony by Lay Witnesses,” Fed. R. Evid. 701, and “Testimony by Expert Witnesses,” Fed. R. Evid. 702. The lay opinion rule “does not permit a lay witness to express an opinion as to matters which are beyond the realm of common experience and which require the special skill and knowledge of an expert witness.” This means that “knowledge derived from previous professional experience falls squarely within the scope of Rule 702 [governing expert testimony] and thus by definition outside of Rule 701 [lay opinion testimony].” In the context of police testimony purporting to interpret drug code language, “testimony based on knowledge derived from the investigation of the case at hand is typically regarded as lay testimony, opinion testimony premised on the officer’s professional experience as a whole is expert testimony.” Although not addressed in Cristerna-Gonzalez, the lay/expert boundary is crucial because it determines whether a summary of expert testimony must be provided and whether Daubert is implicated.
Second, citing a federal rules of evidence treatise and the ABA’s Civil Trial Standards, the Cristerna-Gonzalez panel signaled its disapproval of the common prosecution tactic of causing the trial judge to endorse a witness as an “expert” in front of the jury. The panel cited particularly helpful language from the comment to the relevant ABA Civil Trial Standard:
[T]here is no need for the court to announce to the jury that it has found that a witness is an expert or that expert testimony will be permitted. The use of the term “expert” may appear to a jury to be a kind of judicial imprimatur that favors the witness.
Because expert testimony is not entitled to greater weight than other testimony, the practice of securing what may appear to be a judicial endorsement is undesirable.
1. Object at trial to expert testimony from police officers if the government did not comply with the notice requirements of Rule 16 or any pretrial scheduling order.
2. Has there been notice? Before trial, challenge the officer's qualifications and the basis for his or her proposed testimony (is it really based on sufficient facts or data?). In other words, put the government through its Rule 702/Daubert paces.
3. Did you lose that challenge? Move the district court in limine to prevent the government from seeking to have the court endorse the officer as an "expert" in front of the jury.