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Monday, November 22, 2021

Revisiting Daubert: Judicial Gatekeeping and Expert Ethics in Court

Young, G., Goodman-Delahunty, J.
Psychol. Inj. and Law (2021). 


This article calls for pragmatic modifications to legal practices for the admissibility of scientific evidence, including forensic psychological science. We submit that Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) and the other two cases in the U.S. Supreme Court trilogy on expert evidence have largely failed to accomplish their gatekeeping goals to assure the reliability of scientific evidence admitted in court. Reliability refers to validity in psychological terms. Part of the problem with Daubert’s application in court is the gatekeeping function that it ascribes to judges. Most Daubert admissibility challenges are rejected by judges, who might lack the requisite scientific expertise to make informed decisions; educating judges on science might not be an adequate solution. Like others who have put forth the idea, pursuant to Federal Rule of Evidence (FRE) 706, we suggest that court-appointed impartial experts can help judges to adjudicate competing claims on admissibility. We further recommend that an expert witness ethics code sworn to in legal proceedings should be mandatory in all jurisdictions. The journal Psychological Injury and Law calls for comments and further recommendations on modifying Daubert admissibility challenges and procedures in civil and criminal cases to develop best practices to mitigate adversarial allegiance and other unconscious biases in expert decision-making.

Advantages of an Expert Witness Ethics Code Sworn to in Legal Proceedings

We suggest that in the field of psychological injury, jurisdictions in which courts reinforce expert obligations via an ethics code for expert witnesses will lead to more balanced and impartial testimony. The essential principle guiding a science-based expert witness ethics code sworn to in legal proceedings is that the process of forensic assessment, as well as the subsequent proffer of testimony in court based on those assessments, should account for all the reliable evidence gathered in a particular case as determined by methodologies informed by scientific research in the relevant field.  This recommendation is in line with psychological research showing that expert bias is reduced when experts do not focus on a single question or hypothesis, but address a “line up” of competing and alternative conclusions and hypotheses (Dror, 2020). The components of the expert witness oath, like the appointment of a court-appointed expert, encourage experts to adopt a differential diagnosis approach, in which all different conclusions and their probability are presented, rather than one conclusion (Dror, 2020). Opinions, interpretations, and conclusions based on the data, information, and evidence will more likely be impartial, fully scientifically informed, and just.