By David Michaels

Dr. David Healy is the probably the single person most responsible for identifying the link between anti-depression drugs like Zoloft and suicide risk. His work led to the FDA to require the addition of a “black box” to the label of selective serotonin reuptake inhibitors (SSRIs), warning of the increased risk for “suicidality.” A few years before the FDA instituted this policy, Dr. Healy was asked to testify about the effects of Zoloft in a lawsuit filed by the parents of Matthew Miller, a teenager who hanged himself soon after starting taking the drug for depression. Healy never took the stand. As Barry Yeoman’s important article Science in the Dock in this week’s issue of The Nation explains, the judge hearing the case refused to allow Dr. Healy to testify, ruling that his belief in the SSRI-suicide link is a “distinctly minority view.”

Dr. Healy was “Dauberted”. The same thing has happened to other respected scientists. Yeoman describes in alarming detail how the Supreme Court’s 1993 ruling in Daubert v. Merrell-Dow has had troubling consequences.

The Project on Scientific Knowledge Public Policy (SKAPP) has examined the genesis and impact of the Daubert decision at great length. In 2003, we issued a report on the tenth anniversary of the decision: Daubert: The Most Influential Supreme Court Decision You’ve Never Heard Of.

In 2005, we helped put together a special issue of the American Journal of Public Health devoted to the use and misuse of scientific evidence in the U.S. judicial system.

Through a special arrangement with AJPH, we’ve put the entire issue up on the SKAPP website for free down-loading. The issue is filled with terrific papers by Sheila Jasanoff, Susan Haack, Margaret Berger, Joe Cecil, George Lakoff, and Peter Neufeld, among other luminaries. The conclusions of my editorial Scientific Evidence and Public Policy are as true today as they were then:

In June 1993, the US Supreme Court ordered federal trial judges to become “gatekeepers” of scientific testimony. Under the Daubert decision and two related Supreme Court rulings, trial judges are now required to evaluate whether any expert testimony is both “relevant” and “reliable.” What began as a well-intentioned attempt to improve the quality of evidentiary science has had troubling consequences. The picture is disturbing: on the basis of a lay judge’s ruling, respected scientists have been barred from offering expert testimony in civil cases, and corporate defendants have become increasingly emboldened to cavalierly accuse any adversary of practicing “junk science.” Such a challenge requires a wealth of resources. Thus in a striking contrast to civil actions where defendants are usually corporations, scientific standards are not rigorously applied in criminal trials, sometimes costing innocent and impoverished defendants their freedom, if not their lives. Increasingly, scientific evidence which is relied upon by federal regulatory agencies – charged with protecting public health – is being subjected to Daubert-like challenges. All three developments – in civil actions, criminal trials and rulemaking – favor the powerful in our society over the weak and vulnerable.

Close analysis of the Supreme Court decision reveals a series of concerns. The requirements Daubert imposes on federal judges are unreachable—no absolute criteria exist for assessing the validity of scientific evidence. Scientific reasoning is no more susceptible to a mechanical approach than legal reasoning. Checklists of criteria, while appealing in their convenience, are inadequate tools for assessing causation. Alternatively, judges may rely on their own experience and “common sense,” which has inherent biases and limitations.

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Daubert has also resulted in judges arbitrarily selecting one scientific discipline (e.g. epidemiology) over another (e.g. toxicology) in positing scientific validity. Uncertainty in science, which is the norm not the exception, does not mean the science is flawed, nor do disagreements among scientists mean that one of the parties is wrong or is using “junk science.”

Further, the criteria that make scientific claims valid within scientific settings are not easily transferable to legal settings. As Sheila Jasanoff writes, “the grand question for the law is not how judges can best do justice to science; the more critical concern is how courts can better render justice under conditions of endemic uncertainty and ignorance.”

The likelihood that questions of scientific validity are raised in a legal proceeding is related to the wealth of the parties involved. Indigent defendants in criminal trials, for example, are rarely capable of hiring experts to counter questionable science that purports to link them with a crime. In contrast, corporate defendants often hire teams of lawyers and scientific experts to use Daubert to make it difficult and costly for plaintiffs to put on their scientific cases through expert witnesses. The tobacco industry, for example, used its extensive resources to challenge the testimony of numerous expert witnesses; it recognized that driving up the costs to plaintiff attorneys would help insulate the industry from legal accountability for producing a dangerous product. Overall, it appears that Daubert has likely discouraged plaintiffs without scientifically sound claims from pursuing them in court, but others with strong claims but insufficient resources have also been prevented from pursuing just compensation for injury.

Yeoman’s article describes the investigations Dr. Healy conducted into SSRIs and suicide risk, and the accumulation of research that eventually vindicated him. By the time the science got to the point that no judge could plausibly claim that Healy’s views were “distinctly minority,” the lawsuit of Matt Miller’s parent had been dismissed.

As I said in the article, we need tools to make sure that bad science doesn’t get to court, but Daubert is an imprecise tool, and its application has resulted in miscarriages of justice.

David Michaels heads the Project on Scientific Knowledge and Public Policy (SKAPP) and is Professor and Associate Chairman in the Department of Environmental and Occupational Health, the George Washington University School of Public Health and Health Services.