Scientific Evidence and the Ethical Obligations of Attorneys

This article considers the question: "What are the legal and ethical responsibilities of attorneys when offering scientific expert evidence to courts?" To a lesser extent it considers the responsibilities of attorneys to challenge such evidence when proffered and the ethical dimensions of the working relationship of lawyers and experts. Although the most prominent discussions of such issues have concerned so-called junk science in civil trials, the legal context upon which this article will focus is the criminal trial, where dubious science is more common, less questioned, and has even become institutionalized. The rules and practices of civil cases are provided for the illuminating contrasts they provide. This article reviews an array of ethical issues affecting the relationship of expert witnesses with lawyers and courts, especially in the criminal justice system.

Changes in the law governing the admissibility of expert testimony, and growing societal concerns about flaws in the criminal trial that permit innocent people to be convicted, have inevitably changed the responsibilities of both proponents and opponents of expert evidence in criminal trials, so far without much awareness of these changes by the lawyers themselves. The familiar tension between the ethical obligations of attorneys and their motivation to win their cases faces new strains in the arena of expert witnesses.