Article by Joëlle Anne Moreno
In the aftermath of September 11, “Americans have apparently heeded the U.S. government's advice to prepare for terror attacks, emptying hardware store shelves of duct tape.” Before rushing out to buy duct tape, you should be forewarned that according to the United States Court of Appeals for the District of Columbia, duct tape is a “tool of the narcotics trade.” This means that a police officer expert testifying for the prosecution may properly tell the jury that duct tape “is often used ‘by people in the drug world to bind hands, legs, and mouths of people who are either being robbed in the drug world or who need to be maintained.”’
Judges routinely admit expert testimony offered by prosecutors, but frequently exclude expert testimony offered by the defense. A review of federal criminal court cases reveals that 92% of prosecution experts survive defense challenges, while only 33% of defense experts survive challenges by federal prosecutors. A recent study of federal appellate criminal cases found that more than 95% of prosecutors' experts are admitted at trial, while fewer than 8% of defense experts are allowed to testify. Why do judges consistently fail to scrutinize prosecution experts? Maybe it is the uniform. The most common prosecution expert witness is a police officer or a federal agent. In state and federal criminal trials, law enforcement experts are routinely permitted to testify to opinions and conclusions derived from their on-the-job experience and personal observations. Prosecutors rely on police officer experts most frequently in narcotics cases. In drug cases, law enforcement experts are often asked to interpret ambiguous words or phrases used by the defendant and/or his coconspirators. The purpose of, and problem with, this expert testimony is that it tells jurors precisely which inculpatory inferences they should draw from the factual evidence.
Cases from all of the federal circuits reveal that judges readily accept prosecutors' empirically unsupported assumption that jurors need police experts “to explain both the operations of drug dealers and the meaning of coded conversations about drugs.” Defense attorneys who seek exclusion based on a more critical judicial analysis—arguing that jurors can understand drug-related words without assistance, that jurors should be permitted to draw their own inferences, or that any arguable relevance is “substantially outweighed by the danger of unfair prejudice” to the defendant—invariably fail.
Why should we be concerned that police experts often play a crucial role in obtaining convictions? At a minimum, this fact demonstrates that the Daubert revolution, aimed at upgrading the quality of expert evidence, has had surprisingly little impact in the criminal courts. Eleven years after Daubert and four years after Federal Rule of Evidence 702 was amended to include a more explicit reliability requirement, the most common type of prosecution expert testimony continues to escape judicial scrutiny. A review of the relevant case law demonstrates that Daubert and Rule 702 have failed in their promise to create consistent and equitable admission standards in the criminal courts. Judges abjure their gatekeeping responsibilities when they fail to scrutinize an expert's qualifications, methodology, and application of these methods to the facts. But more careful pretrial screening is only a partial solution. Once the police expert takes the stand, the court must control the scope of her testimony. Currently, judicial control of prosecution experts is so lax that “hardly a day goes by when some beat cop or narcotics detective somewhere isn't testifying as an expert about one thing or another, from the intent of a defendant caught with drugs to the organizational structure and hierarchy of street gangs.” This can include highly speculative testimony, such as telling the jury that the “fact” that a defendant had rolled up his pants leg meant that he was selling drugs. It can also include expert inferences and conclusions about a defendant's purpose or intent, such as telling the jury that a defendant's statement “I was on that last night, plus we're going to be on that tonight,” means that he was planning to “locate or find some individual and hurt them.” This type of testimony, grounded only in an expert's subjective on-the-job experience, continues unabated as courts consistently reject defense challenges based on Federal Rules of Evidence 702, 704(b), or 403. Problems of prejudice and confusion also arise when, as is often the case, the law enforcement expert is the investigating officer. The circuits are in significant disagreement about whether police expert testimony should be limited to the officer's general knowledge or whether it may properly include specific inferences drawn from facts developed during the investigation of the defendant's case. Problems abound when experts make inferences and draw conclusions that rely on factual evidence derived from their own investigations. The dual role of fact and expert witness contains a built-in incentive for the witness to shape the facts to fit the opinion or the opinion to fit the facts. Witnesses can also deliberately or unintentionally blur the distinction between fact and opinion misleading or confusing jurors in violation of Rule 403. Whenever an expert draws from personal knowledge gained during an investigation from sources that have unestablished reliability, it also increases the likelihood that her testimony will contain otherwise inadmissible evidence. Finally, judicial qualification of a police officer as an “expert” can imbue all of her testimony, including her fact testimony, with an aura of neutrality or expertise that can artificially enhance her credibility.
We have a problem when twenty-first-century criminal courts seem like the Wild West to the expert who carries a gun and a badge. Recent empirical data and a review of relevant cases reveal that law enforcement experts who serve as members of the prosecution team have essentially unfettered access to juries. It is inarguable that jurors may require expert assistance analyzing foreign or unfamiliar evidence in some cases. When police officers have necessary expertise and can demonstrate the reliability of their methods and the proper application of these methods to the appropriate facts, they should be permitted to testify. However, there is no excuse for failing to subject expert opinions to the more rigorous scrutiny required by any reasonable reading of Daubert, General Electric Co. v. Joiner, Kumho Tire Co. v. Carmichael, and the new Rule 702. The complex problems endemic to law enforcement expert testimony have been ignored for too long by judges easily satisfied with a cursory review of expert qualifications and perfunctory acceptance of a panoply of a police opinions and conclusions.
There is no quick fix that will stem the tide of judicial permissiveness, but there are six sources of hope. First, the beefed-up reliability requirement added to Rule 702 provides new arguments for rigorous judicial scrutiny of all expert evidence. Second, the United States Court of Appeals for the Ninth Circuit recently became the first federal appellate court to use Rule 702 to assess the reliability of drug jargon expert testimony. Third, Kumho Tire requires that an expert “employs in the courtroom the same level of intellectual rigor” as in her chosen field. This is impossible because drug jargon is not a legitimate field of study. Fourth, even when judges opt to admit expert testimony, a series of recent circuit court cases suggest that judges must still limit experts' testimony at trial. Fifth, the previously unexplored relationship between drug jargon testimony and propensity evidence may be an untapped source of effective defense arguments. Finally, this exploration of how prosecutors use police experts raises serious questions about how to best ensure that evidentiary standards do not prejudice criminal defendants.
It is worth mentioning from the start that police officers will sometimes accurately opine that “pianos,” “boyfriends,” “briefs,” and “motions” are code words for heroin. But dispensing with judicial scrutiny because expert testimony is potentially reliable is akin to dispensing with suppression hearings because they involve potentially reliable and inevitably inculpatory evidence. The post-September 11 future enhances the dangers of judicial deference to police experts as law enforcement and prosecutors become endowed with even greater actual and perceived authority. It is time for criminal courts to recognize that conscientious judicial oversight is critical in all prosecutions that rely on police officer expertise.
About the Author
Joëlle Anne Moreno. Associate Professor of Law, New England School of Law.
Citation
79 Tul. L. Rev. 1 (2004)