THE TRAINED PSYCHOLOGIST AS EXPERT WITNESS

Judgment research is described and related to forensic assessment. Topics include (a) the relation between training and accuracy of judgements, (b) our ability to identify clinicians who are good at a judgment task, (c) the reliability and validity of judgments made by mental health professionals and neuropsychologists, (d) the cognitive process of clinicians, and (e) the validity of statistical prediction rules. Research indicates that expert testimony can be useful as long as clinicians are aware of the limitations of their expertise. Clinicians are able to make reliable and valid judgments for many tasks, and their judgments are frequently more valid than judgments made by laypersons.