Increasing the reliability, validity and relevance of psychological expert evidence: An introduction to the Special Section on Expert Evidence

Stephen L. Golding

Department of Psychology

University of Utah

Salt Lake City, UT

The structure of our jurisprudence, both civil and criminal, is based, in part, upon a variety of theories and expectations of human behavior, perception, intentionality and judgment. As a consequence, social scientists, in general, and psychologists, in particular, are called upon, with increasing frequency, to offer expert evidence. Expert witnesses differ in many respects from other witnesses, the most important difference being that they are permitted or even encouraged to offer opinions and inferences, often on the basis of evidence that is not otherwise admissible. It should therefore come as no surprise, within the adversarial context of our judicial system, that the powerful advantages and disadvantages of admitting such testimony have been the subject of centuries of strident controversy and debate. The controversies have centered on a variety of topics, the most common being a) the lack of scientifically acceptable theories and methods; b) the question of whether such witnesses are impartial experts as opposed to advocates, "oath helpers," or "secret moral agents;" c) the inadequacy of judicial procedures for selecting and qualifying experts; d) the prejudicial impact of expert testimony and the degree to which such testimony may abridge fundamental rights; e) the distortion of scientific expertise in an adversarial system; and finally, f) the extent to which expertise is "for hire" (***). In response to such critiques, the American Psychology-Law Society, Division 41 of the American Psychological Association and the American Academy of Forensic Psychology have adopted the Specialty Guidelines for Forensic Psychologists (***) in an attempt to provide guidance to both the judicial system and forensic professionals and to improve the quality of forensic psychological evidence. This Special Section of Law and Human Behavior is similarly designed to increase the quality of such evidence by providing critical review and commentary about a set of issues commonly confronted by the courts and our profession. Please note, however, that because these articles were selected from those submitted, they should not be taken as representing all of the important issues in this area.

I would like to take this opportunity to comment upon some general themes which emerge from this set of articles. First, and perhaps foremost, there is a great deal of confusion and ambiguity about the "ground rules" for the admissibility of expert psychological evidence. The rules vary from jurisdiction to jurisdiction and from context to context. Adding to the confusion is a tendency for legal rules to use the term "reliability" where a social scientist would use the term "construct validity." The papers in this section will help mental health professionals in understanding the existing rules of admissibility in specific contexts, but clearly we must assist the judicial system by contributing to a coherent and scientifically sound conceptual framework for the analysis of psychological evidence.