Attorney beliefs concerning scientific evidence and expert witness credibility

Abstract

Expert witnesses play a pivotal role in offering a variety of scientific evidence at trial. Although judges are the ultimate gatekeepers of what constitutes valid scientific evidence, attorneys play an important part in determining what evidence is presented to the court. Employing experimental and descriptive analyses, the present study sought to address gaps in the attorney/expert witness literature by addressing three questions: One) To what extent do attorneys prefer forensic or social scientific evidence and experts?, Two) How knowledgeable are attorneys concerning empirically-supported indicators of expert credibility?, Three) What do attorneys believe concerning the frequency and nature of expert errors in their own trials relative to others? Results showed that attorneys prefer forensic science evidence and experts compared to social/psychological counterparts. Moreover, attorneys displayed considerable knowledge of factors that will impact perceived expert credibility. In particular, attorneys value perceived expert trustworthiness, communication skills, content of testimony/reports, perceived expert knowledge, and years and type of expert experience. Finally, attorneys displayed a consistent and strong self-serving bias pattern, such that they believe expert errors occur more much frequently in other attorneys' cases compared to their own. Implications are discussed with respect to vetting expert witnesses, scientific evidence/errors and wrongful conviction, and training for attorneys.