Increasingly, in a number of contexts, experts are playing the role traditionally filled by attorneys: reviewing and explaining the relevance of the evidence, integrating it into the party’s narrative, and mixing in opinions along the way. This has the potentially dangerous effect of placing the authority of an expert behind what is effectively a protracted version of a closing argument.

Recently, the US Court of Appeals for the Fourth Circuit created significant obstacles to at least some aspects of this type of expert testimony in United States v. Garcia, 2014 WL 1924857 (4th Cir. May 15, 2014). Garcia involved a prosecution for narcotics possession with intent to distribute. Central to the Government’s case was an FBI Special Agent who testified both as a fact witness, based on her participation in the investigation, and as an expert witness, based on years of experience deciphering drug-trade slang. The agent’s testimony consisted, in large part, of deciphering wire-taped conversations that allegedly involved coded references to drug transactions. The Fourth Circuit reversed the resulting conviction, holding that “there were inadequate safeguards to protect the jury from conflating [the agent’s] testimony as an expert and fact witness.” Although Garcia was a criminal case, the limitations on expert testimony it imposed apply equally in the civil context. The errors identified by the court fall into three related categories.

First, there were “repeated instances of [the agent] moving back and forth between expert and fact testimony, with no distinction in the Government’s questioning or in [the agent’s] answers.” For example, the agent interpreted the phrase “a hundred forty five point” to mean 145 grams of heroin. Although presented as expert testimony, this “simply substituted information gleaned from [the agent’s] participation in the investigation”—specifically, interviews related to the seizure of 145 grams of heroin—“for her ostensible expertise.” By failing to distinguish between expert opinion and fact testimony, the Government was able to present information the agent garnered from non-testimonial evidence, through the guise of expert opinion, without subjecting that evidence to the normal rules of admissibility.

Second, the agent repeatedly “‘decoded’ words and phrases that needed no expert translation at all since the meaning was either apparent on its face or apparent with contextual information that any fact witness could have provided.” Instead of presenting the evidence through fact witnesses and letting the jury decide whether the Government had established a connection between various pieces of evidence, the agent used her imprimatur as an expert to draw that connection for the jury. “But cloaking this connection in the guise of expert testimony goes beyond what is contemplated under Federal Rule of Evidence 702 …. The Rule contemplates that an expert’s opinion testimony will be ‘helpful to the jury,’ not merely helpful to the prosecutor as transmutations of simple fact testimony.”

Finally, the Government not only failed to distinguish between the expert and factual bases for the agent’s testimony, it repeatedly failed to lay a foundation (from either source) for interpretations offered by the expert. For example, the agent interpreted the term “show time” in a telephone conversation to mean heroin, but “[t]here was no explanation as to what, in the context of the call or otherwise, led her to believe that ‘show time’ meant ‘heroin.’” Because the agent did not explain the foundation for a number of opinions, the Fourth Circuit concluded that “the record fails to demonstrate the requisite reliability in [the agent’s] execution of her claimed methodology.”

Under Garcia, it must be clear to the jurors when an expert is testifying based on a review of the evidence in the case and when the expert is giving opinions based on external expertise. And, in both instances, an appropriate foundation must be laid: Simply prefacing each statement with “in my expert opinion” is not enough. Moreover, each substantive question answered by an expert should be designed to aid the jurors by providing insight that an average lay juror does not possess. An expert is not there to tell the party’s story, but to provide targeted information that is within the expert’s area of expertise. Anything more “goes beyond what is contemplated under Federal Rule of Evidence 702” because it is helpful only to the party offering the expert, and does not aid the jury in performing its role as the neutral arbiter of the facts.