In the article “Standards of Practice and Care in Forensic Mental Health Assessment. Legal, Professional, and Principal Based Consideration” the authors discuss three key principals that according to the them, "should help minimize arbitrariness in the legal decision-making process through promoting thoroughness, consistency, and impartiality." The goal is create a sense of consistency among forensic analyses.
In forensics, it is very important to produce legal sound consistent data. The use of reliable data is paramount in forming opinion. There is also a deep need to provide third party sources to insure that information is valid. Strategies are required for addressing styles of response and use scientific reasoning. Since forensic assessments are often for use in courts, confidentiality is not as important and others may be consulted to help form an informed diagnosis. The ability for all information to hold up in a court of law and carefully documented assessments with the use of proper coding is very important.
These qualities differ slightly from standard practice of mental health assessment. Traditional assessments are often confidential and rely more on emotion and opinion than actual facts. The knowledge and the opinions of the psychologist often effect the findings. The extra step of insuring that the information is valid is not as complex. Traditional forms of assessment are not as systematic and may vary greatly from psychologist to psychologist who all have their own unique style based on personal knowledge. The availability of information from the patient is easier to obtain and often deals with their emotional response from the assessment.
Overall, both forensic and traditional mental health assessments use prior knowledge to complete assessments, however forensic assessments are much more reliant on third party information.
Heilbrun, Kirk; DeMatteo, David; Marczyk, Geoffrey; Goldstein, Alan M. (2008). Standards of Practice and Care in Forensic Mental Health Assessment. Legal, Professional, and Principles-Based Considerations. Psychology, Public Policy, and Law, 14, (1) . (Pages 1-26)