Forensic psychology is the intersection between
psychology and the
criminal justice system. It involves understanding criminal law in the relevant
jurisdictions in order to be able to interact appropriately with
judges,
attorneys and other
legal professionals. An important aspect of forensic psychology is the ability to
testify in court, reformulating psychological findings into the legal language of the courtroom, providing information to legal personnel in a way that can be understood.
Further, in order to be a
credible witness, for example in the United States, the forensic psychologist must understand the philosophy, rules and standards of the American judicial system. Primary is an understanding of the
adversarial system. There are also rules about
hearsay evidence and most importantly, the
exclusionary rule. Lack of a firm grasp of these procedures will result in the forensic psychologist losing
credibility in the courtroom.
A forensic psychologist can be trained in clinical, social, organizational or any other branch of psychology.
In the United States, the salient issue is the designation by the court as an
expert witness by training, experience or both by the judge. Generally, a forensic psychologist is designated as an expert in a particular jurisdiction. The number of jurisdictions in which a forensic psychologist qualifies as an expert increases with experience and reputation.