Goals of Forensic Assessment

  • Evaluation of possible malingering
  • Assessment of mental state/insanity
  • Competency to stand trial
  • Predict risk for violence
  • Custody issues
  • Personal injury assessment
  • Polygraph data

Standards for Expert Witness

  • must be qualified
  • must present information beyond basic juror knowledge
  • value of evidence must outweigh its prejudicial effect
  • testimony must be in accordance with a generalluy accepted theory

Legal Standards

  • Frye vs. United States (1923)
    Federal and state courts categorically rule polygraph evidence inadmissible under the test set forth in Frye v. United States, 293 F. 1013 (CADC 1923), which held that scientific evidence must gain the general acceptance of the relevant expert community to be admissible, and stated that polygraph testing did not meet that criterion.
  • Daubert vs. Merrell Dow Pharmaceuticals (1993)
    In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U. S. 579 (1993), the court held that Frye had been superseded by the Federal Rules of Evidence and that expert testimony could be admitted if the district court deemed it both relevant and reliable.
  • M'Naughten rule
    a traditional "right and wrong" test of legal insanity in criminal prosecutions. Under M'Naughten (its name comes from the trial of a notorious English assassin in the early 1800s), a defendant is legally insane if he/she cannot distinguish between right and wrong in regard to the crime with which he/she is charged. If the judge or the jury finds that the accused could not tell the difference, then there could not be criminal intent. Considering modern psychiatry and psychology, tests for lack of capacity to "think straight" (with lots of high-priced expert testi-mony) are used in most states either under the American Law Institute's Model Penal Code or the "Durham Rule." (From http://dictionary.law.com/)
  • Durham Rule
    States an accused is not criminally responsible if his unlawful act was the product of mental disease or defect. Based on Durham v. United States (D.C. Cir. 1954)