Flawed forensics in criminal trials overlooked in push to reform expert witness rules

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REUTERS/Chip East

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(Reuters) - The federal judiciary is considering changing the rules of evidence to make it harder for “expert” witnesses to present pseudo-scientific and unreliable evidence at trials.

The process has been largely centered on concerns from corporate defense lawyers about civil cases and torts – litigation against big businesses, often over injuries allegedly caused by drug and other consumer products.

But the more important reasons to change the Federal Rules of Evidence regarding expert witnesses are in the criminal law realm.

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Nationwide and systemic problems in forensic sciences have been documented over several decades in various studies, and numerous public scandals related to false convictions, often enabled by state crime labs.

The Federal Bureau of Investigation’s crime lab, touted as the best in the world, stopped using bullet lead examinations in 2005 after a report concluded there was no scientific basis for matching a particular bullet at a crime scene with an unused batch of ammunition. The FBI had used compositional bullet lead analysis since the 1960s.

Since then, the country’s leading scientific advisory bodies have found that some routinely used forensics methods are wholly unsubstantiated and lack a scientific foundation.

The National Academy of Sciences conducted the most comprehensive review to date of forensics in the United States. It concluded in a 2009 report that many methods are routinely “introduced in criminal trials without any meaningful scientific validation, determination of error rates, or reliability testing to explain the limits of the discipline.”

The study also found that “prosecutors usually have an advantage over most defendants in offering expert testimony in criminal cases,” while both sides have about equal access to experts in civil cases.

“The research shows a clear divide between how courts treat scientific evidence in toxic tort cases, for example, and how they treat it in criminal cases,” said Edward Cheng, a professor at Vanderbilt Law School who served as a commentator on panels designed to aid the judiciary’s efforts to amend the expert witness rule. “Basically, they tend to be very lax about letting in forensic stuff in the criminal context, whereas they’re defendant-friendly on the tort side.”

A review by the President’s Council of Advisors on Science and Technology in 2016 also concluded that certain forensic fields aren't grounded in science. It was that 2016 report, in part, that led the courts to appoint a subcommittee and spend four years considering possible amendments to the expert testimony rule, according to a May 2021 memo by Judge Patrick Schiltz, chair of the federal judiciary’s Advisory Committee on Evidence Rules.

So, then, why is the federal judiciary focused on civil cases in considering changes to expert testimony?

No doubt, tort cases are high-stakes, often implicating millions of dollars, and depend in large part on medicinal and other kinds of scientific and technical expertise. But they aren’t usually matters of life or death, or freedom or imprisonment – and they don’t reflect on the integrity of the justice system in quite the same way as a doubtful, or wrongful, conviction.

A spokesperson for the Administrative Office of the U.S. Courts referred me to the reports and materials produced by the rules committees. The office didn't respond to my specific questions for this column.

The current proposal to amend Rule 702 of the Federal Rules of Evidence says a party must prove by a preponderance of evidence that an expert’s testimony is admissible – a requirement that wasn’t explicitly stated before. And it would emphasize that judges must ensure that experts’ opinions are actually based on a reliable application of their methodologies in a particular case.

Nearly all the public comments and support for the proposal have come from the civil defense bar.

D. Michael Risinger, emeritus professor at Seton Hall University School of Law and previous chair of the Association of American Law Schools Section on Evidence, told me the proposals are largely restatements of current law.

“I don’t know if those changes will help anybody much – other than corporate defendants” who can plausibly argue that the amendments are intended for their cases, Risinger said. He added that the process could be improved in the criminal context with an amendment clarifying that judges should determine the reliability of a methodology as applied to specific questions in a case (whether handwriting analysis can determine authorship of a single, allegedly forged signature, for example, rather than whether that methodology is valid for determining authorship in other contexts, like for a lengthy, personal letter).

All things considered, the judiciary’s focus on corporate defendants isn’t particularly surprising.

Paul Giannelli, emeritus professor at Case Western Reserve University School of Law, wrote in a 1993 law review article that “the ‘junk science’ debate has all but ignored criminal prosecutions” – including the judiciary’s considerations of amendments at that time. “This neglect of the problems of expert testimony in criminal prosecutions is deplorable, if not inexplicable,” Giannelli said.

In 2018, JoAnne Epps, a professor at Temple University’s Beasley School of Law, wrote that criminal trials have taken “a backseat to tort claims in the debate over expert evidence” since the 1990s.

One recent proposal in the ongoing amendment process was ostensibly aimed at criminal trials.

Cheng said a proposal to ban “overstatement” by experts – testifying that a finding is 100% certain, for example – was likely to improve safeguards in that context.

But the committee ultimately discarded that proposal: members said the rules already bar overstatement, and were concerned about the “unintended consequences” for experts outside of the forensics and criminal contexts, according to the report from Judge Schiltz.

To be sure, there are serious complications in devising and articulating a single test or set of principles to adequately deal with the vast range of expertise – scientific and otherwise – relevant to litigation. And, there are contributing factors to the forensic sciences problem that aren’t in the judiciary’s purview – like the lack of a well-funded, well-staffed indigent criminal defense system to challenge those proffered experts.

But the judiciary’s neglect of the glaring and more critical systemic problems around scientifically invalid forensics reflects an elevation of the interests of big businesses over average people who come before the courts. And it’s a missed opportunity to more directly address problems that undermine the administration of justice itself.

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Hassan Kanu writes about access to justice, race, and equality under law. Kanu, who was born in Sierra Leone and grew up in Silver Spring, Maryland, worked in public interest law after graduating from Duke University School of Law. After that, he spent five years reporting on mostly employment law. He lives in Washington, D.C. Reach Kanu at hassan.kanu@thomsonreuters.com