The assessment of personality variables.
Psychological assessment is used for a variety of purposes, ranging from screening job applicants to providing data for research projects. Most assessment methods fall into one of three categories: observational methods, personality inventories, or projective techniques.
Observational assessment is performed by a trained professional either in the subject's natural setting (such as a classroom), an experimental setting, or during an interview. Interviews may be either structured with a standard agenda, or unstructured, allowing the subject to determine much of what is discussed and in what order. Impressions gained from interviews are often recorded using rating scales listing different personality traits. Expectations of the observer, conveyed directly or through body language and other subtle cues, may influence how the interviewee performs and how the observer records and interprets his or her observations.
Personality inventories consist of questionnaires on which people report their feelings or reactions in certain situations. They may assess a particular trait, such as anxiety, or a group of traits. One of the oldest and best known personality inventories is the Minnesota Multiphasic Personality Inventory (MMPI), a series of 550 questions used to assess a number of personality traits and psychological disturbances for people over age 16. The MMPI is scored by comparing the subject's answers to those of people known to have the traits or disturbances in question. While initially designed to aid in the diagnosis of serious personality disorders, the MMPI is now widely used for persons with less severe problems, as enough data has been collected from this population to allow for reliable interpretation of test results. One problem with personality inventories is that people may try to skew their answers in the direction they think will help them obtain their objective in taking the test, whether it is being hired for a job or being admitted to a therapy program. Validity scales and other methods are commonly used to help determine whether an individual has answered the test items carefully and honestly.
A projective test gives the subject a greater opportunity for imaginative freedom of expression than does a personality inventory, where the questions are fixed beforehand. Projective tests present individuals with ambiguous situations which they must interpret, thus projecting their own personalities onto those situations. The best known projective test is the Rorschach Psychodiagnostic Test, or inkblot, test first devised by the Swiss psychologist Hermann Rorschach in the 1920s. The test subject describes his or her reactions to elaborate inkblots presented on a series of ten cards. Responses are interpreted with attention to three factors: what parts or parts of each inkblot the subject responds to; what aspects of the inkblot are stressed (color, shape, etc.); and content (what the inkblot represents to the subject). Another widely used projective test is the Thematic Apperception Test (TAT), developed at Harvard University in the 1930s. In this test, the subject is shown a series of pictures, each of which can be interpreted in a variety of ways, and asked to construct a story based on each one. Responses tend to reflect a person's problems, motives, preoccupations, and interpersonal skills. Projective tests require skilled, trained examiners, and the reliability of these tests is difficult to establish due to their subjective nature. Assessments may vary widely among different examiners. Scoring systems for particular traits have been fairly reliable when used with the Thematic Apperception Test.
Handbook of Psychological Assessment. New York: Wiley, 1990.
Personality and Ability: The Personality Assessment System. Lanham, MD: University Press of America, 1994.