Psychological assessment contributes important information to the understanding of individual characteristics and capabilities, through the collection, integration, and interpretation of information about an individual. Such information is obtained through a variety of methods and measures, with relevant sources determined by the specific purposes of the evaluation.

Such testing (psychometry) can assist in diagnosing conditions like Mental Retardation (Intellectual Disability), Autism, Specific Learning Disability (SLD), ADHD, understanding personality, finding persisting errors in thinking, maladaptive coping patterns, understanding self-harming patterns or suicidality, exploring relationship issues, exploring repressed trauma and grief, understanding unresolved conflicts, exploring sexual problems, etc.

The findings of these testing can be used to assist the treating psychiatrist to fine tune the treatment, and also form the basis/guidance for the therapist to proceed with therapy, be it the type of therapy, or the manner of dealing with the client.