Psychological Test There Have Been Many Definitions

¶ … Psychological Test

There have been many definitions of a test. For example, Kline (1993, P. 16) defines a psychological test as a standardized measure of behavior. Hogan (2007, p.41) considers such definitions lacking and instead offers a more comprehensive definition, "A test is a standardized process or device that yields information about a sample of behavior or cognitive processes in a quantified manner."

Categories of Psychological Tests

According to Hogan (2007) there are five categories of psychological tests. The first category consists of mental ability tests (Hogan, 2007, p. 5). Mental abilities can include a wide variety of cognitive functions such as memory of creative thinking, but most often these are classified as intelligence tests. These tests can be administered in individually, in groups, or other formats. One of the most common individual mental ability tests is the Wechsler Adult Intelligence Scale -- IV (WAIS-IV), whereas Hogan (p. 5) states that a group mental ability test is the Scholastic Achievement Test (SAT). These tests can be used by clinicians, researchers, academic placement services and many others. Mental ability tests are most often used to measure certain cognitive functions in people (such as the WAIS-IV) or to predict performance on another criterion (e.g., the SAT is used to predict college GPA).

The second category of psychological tests is achievement tests (Hogan, 2007, p. 6). These tests are designed to measure the level of knowledge or skill in a particular area that a person has. Of course college classroom tests would be an example here but there are also a number of standardized achievement tests used for this purpose such as the Iowa Tests of Basic Skills. The subcategories of these tests include achievement batteries (many skills), single subject tests, certification and licensing tests, government sponsored tests, and individual achievement tests. These tests are administered by educators, administrators, clinicians, state officials, and others to assess certain skills, predict performances, provide certification, or develop learning programs.

The third category of tests is personality tests (Hogan, 2007, p. 7). The first subcategory of these tests is objective tests. Objective tests are scored in an objective fashion such as a true/false format like the MMPI. Questions are straightforward and allow for specific answers. The other category of personality tests is projective tests, which often consist of ambiguous stimuli and the respondent "projects" their feelings or emotions in the interpretation of the test stimuli as in the Rorschach Inkblot Test. Personality tests are most often administered by clinicians and sometimes administrators of companies. They are used in clinical decisions such as diagnosis and treatment planning, research, and sometimes in hiring or promotion decisions.

The fourth category of psychological tests includes vocational or interest, or attitude tests (Hogan, 2007, p. 8). These tests, such as the Strong Interest Inventory, measure relevant interests of the person and are used in schools and vocational rehabilitation services to help individuals identify viable career/employment options consistent with their interests. They are also used by researchers and clinicians to measure someone's attitudes toward a certain issue or topic.

The final category of tests is neuropsychological tests (Hogan, 2007, p. 8). These tests are used to measure CNS functioning, particularly the functioning of the brain. They are used by clinicians to assist in the determination of the functional aspects of brain damage/dysfunction.

Reliability and Validity

Important psychometric issues in testing include those of reliability and validity.

Reliability

In general the term reliability refers to the consistency of the test measurement or results (Hogan, 2007, p. 112). In the psychometric sense this refers to notions of consistency, replicability, and dependability (Hogan, 2007, p. 113). There are several measures of these facets. Test-retest reliability measures how well a test correlates with itself over different administrations in time (Hogan, 2007, p.131). Inter-scorer reliability measures how the test correlates over different administrators (Hogan, 2007, p. 131). Alternate form reliability measures how different forms of a test relate to each other (Hogan, 2007, p. 133). Internal consistency measures how well the items of a test relate to each other, or measure the same thing (Hogan, 2007, p. 134). Reliability is an extremely important psychometric measure of a test's ability to be useful in terms of its consistency of measurement; however, it is only one important facet. It is quite possible for a test to be reliable and yet not valid. For example measuring the circumference of the head in adults would result a reliable measurement, but it would be a poor indicator of intelligence. However, it is not possible for a test to be valid and yet unreliable, for if a test cannot correlate with itself then it cannot correlate with anything else (Urbina, 2004, p. 151).