Psychological tests are a major resource to assess the intellectual and psychological functioning of individuals. There are, broadly speaking, two kinds of psychological tests: objective and projective. The objective test requires the client to respond in a structured manner, such as true/false, yes/no, a/b/c/d/. The projective test requires the individual to impose his/her interpretations on the material: “Tell me what you see, make-up a story,” and so on.

Personality tests like the Rorschach Inkblot Test, the Thematic Apperception Test (TAT), and the Minnesota Multiphasic Personality Inventory (MMPI) are widely used. The Rorschach consists of 10 symmetrical inkblots. The respondent is asked to inform the tester about what he sees. The TAT consists of 30 pictures categorized for a boys, girls, men, women. The respondent is asked to tell a story about the pictures. The most commonly used objective personality test is the MMPI, which has recently been revised. It consists of 567 items to be answered true or false.

The most widely respected intelligence test for adults is the Wechsler Adult Intelligence Scale Revised (WAIS-R) which provides an intelligence quotient (IQ) . A similar test for children is the Wechsler Intelligence Scale for Children (WISC-III).

Besides assessing general intellectual capabilities, the intelligence test answers a number of other important questions for the psychologist including: (1) Is organic disease or injury present? (2) Is there a thought disorder? (3) Is there an emotional disorder that is impairing intellectual functioning? The patterning of scores on the intelligence test gives the psychologist clues to the presence, extent, and relative influence of organic and personality factors on the expression of intelligence. Intelligence tests are also used to ascertain if a child is gifted or has a learning disability.