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Psychological Evaluations in the Criminal Justice System: Basic Principles and Best Practices

NCJ Number
Aggression and Violent Behavior Volume: 18 Issue: 1 Dated: January/February 2013 Pages: 83-91
Laurence Miller
Date Published
February 2013
9 pages
After discussing the basic principles and best practices in psychological evaluations in the criminal justice system, this article addresses the use of psychological evaluations to determine competency to stand trial, the validity of an insanity defense and diminished capacity, and the prediction of future dangerousness and risk factors for reoffending; and guidance is offered for conducting a forensic psychological evaluation and testifying in court as a forensic psychological expert witness.
Two basic principles are outlined for forensic psychological evaluations. First, the presence, absence, or severity of a diagnosable mental condition does not in itself have legal implications. Second, any conclusions about the relevance of the defendant's mental state to an issue in his/her legal processing must take into account the point in time of the issue's relevance. In outlining guidelines for assessing competency to stand trial, the article focuses on competency criteria related to a defendant's understanding and responsible participation in various features of the trial. The discussion of a psychological evaluation that focuses on a possible insanity defense or diminished capacity specifies the criteria set by the law that must be met in these defenses. The discussion of psychological evaluations that predict future dangerousness and risk factors for reoffending identifies risk factors for reoffending. Another major section of the article identifies and briefly discusses the collection of data and information needed for an evaluation. The article concludes with guidelines for testifying as a forensic psychological expert witness, including how to prepare for the testimony and present oneself on the witness stand. 63 references