The Minnesota Multiphasic Personality Inventory is one of the most widely used multitrait scales. It is developed by Hathaway and McKinley in the 1943 using the criterion-keyed method, a very different method of test construction. It consists of around 567 of statements that reflect attitudes, emotional reactions, physical and psychological symptoms and experiences. The subject is requested to answer "true", "false" or "cannot say" to questions such as "I have trouble falling asleep", depending whether the statements apply to them or not.
The test scales can be categorized into three parts: validity scales, clinical scales and content scales. Content scales contain information on irritability, hotheadedness and other symptoms of anger or control problems. Clinical scales are for identifying psychological disorders such as paranoid personality disorder. Clinical scales are divided into 10 scales.
A person scoring high in this clinical scale may in indicate that the person:
Hypochondrasis - is preoccupied with self, complaining, hostile, and presenting numerous physical problems that tend to be chronic
Depression - is moody, shy, despondent, pessimistic and distressed
Hysteria - tends to rely on neurotic defenses to deal with stress and tends to be dependent, naive and narcissistic
Psychopathic deviation - rebelliousness, impulsiveness, hedonism, antisocial behavior, encountering difficulties in marital or family relationships, and trouble with the law and authority
Masculinity/femininity - Men: departing from traditional gender roles, sensitive, passive or feminine. Women: rough, agressice, unemotional and insensitive and masculine.
Paranoia - suspicious, aloof, shrewd, guarded, worrisome and project blame
Psychasthenia - tense, anxious, Ruminative, preoccupied, obessionsal, rigid, self-condemning
Hypomania - overly energetic, optimistic, amoral, flighty, grandiose and impulsive
Social introversion - introverted, shy, socially-reserved, submissive, over controlled, tense, inflexible and guilt-prone
The MMPI also has questions to test the validity of the clinical and content questions. If the individual's scores two high in one of these questions, the other questions will be interpreted with more care because the individual might have not answered carefully or honestly.
The purpose of MMPI is to help differentiate normal and abnormal groups. It is also specifically designed to assist in the diagnosis or assessment of major psychological disorders. Although the MMPI has been criticized for the weak reliability and validity of some of its scales, it has been useful in identifying people with serious personality disorders.
There are now more than 8,00 published studies on the MMPI, and it has been translated into around 115 languages has proved its usefulness.