Psychological tests can be grouped into several broad categories. Personality tests measure personal qualities, sometimes referred to as traits. Achievement tests measure what a person has learned. Aptitude tests are designed to predict future behaviour, such as success in school or job performance. Intelligence tests measure verbal and/or nonverbal skills related to academic success. Interest inventories are used to help individuals make effective career choices.
Psychological tests are usually administered and interpreted by a psychologist because studies in psychopathology, along with academic courses and supervision in psychological testing, are an integral part of the doctoral degree in clinical psychology. A counsellor who has had the appropriate academic courses and supervision may administer occupational tests or achievement and aptitude tests, but most counselors have not received the training to administer personality tests. Academic courses and supervision in psychological testing are usually not a part of a psychiatrist's medical training, so most psychiatrists can ethically administer only some specific clinical tests that are straight-forward check-lists of symptoms.
Of course, ethics is one thing, and the desire to make money is another thing. Therefore you will often find individuals offering to do all kinds of psychological testing—often on the Internet—even when they lack the training to administer and interpret such tests.
Psychological tests fall into several categories:
1. Achievement and aptitude tests are usually seen in educational or employment settings, and they attempt to measure either how much you know about a certain topic (i.e., your achieved knowledge), such as mathematics or spelling, or how much of a capacity you have (i.e., your aptitude) to master material in a particular area, such as mechanical relationships.
Intelligence tests attempt to measure your intelligence, or your basic ability to understand the world around you, assimilate its functioning, and apply this knowledge to enhance the quality of your life. Or, as Alfred Whitehead said about intelligence, “it enables the individual to profit by error without being slaughtered by it.”
Intelligence, therefore, is a measure of a potential, not a measure of what you’ve learned (as in an achievement test), and so it is supposed to be independent of culture. The trick is to design a test that can actually be culture-free; most intelligence tests fail in this area to some extent for one reason or another.
2. Neuropsychological tests attempt to measure deficits in cognitive functioning (i.e., your ability to think, speak, reason, etc.) that may result from some sort of brain damage, such as a stroke or a brain injury.
3. Occupational tests attempt to match your interests with the interests of persons in known careers. The logic here is that if the things that interest you in life match up with, say, the things that interest most school teachers, then you might make a good school teacher yourself.
4. Personality tests attempt to measure your basic personality style and are most used in research or forensic settings to help with clinical diagnoses. Two of the most well-known personality tests are the Minnesota Multiphasic Personality Inventory (MMPI), or the revised MMPI-2, composed of several hundred “yes or no” questions, and the Rorschach (the “inkblot test”), composed of several cards of inkblots—you simply give a description of the images and feelings you experience in looking at the blots.
Personality tests are either objective or projective.
Objective tests present specific questions or statements that are answered by selecting one of a set of alternatives(eg. true or false). Objective tests traditionally use a "paper-and-pencil" format which is simple to score reliably. Although many objective tests ask general questions about preferences and behaviours, situational tests solicit responses to specific scenarios.
The MMPI - The Minnesota Multiphasic Personality Inventory is the leading objective pesonality test. Its hundreds of true-false items cover a broad range of behaviours. A major advantage of the MMPI is the incorporation of validity scales designed to detect possible response bias, such as trying to present oneself in a socially desirable way.
Projective personality tests use ambiguouis stimuli into which hte test take presumably projects meaning. This indirect type of assessment is believed by many to more effectively identify a person's real or underlying personality.
a. Scoring Projective Techniques
Because the test taker is free to respond in any way, rather than being required to select an answer from a set of alternatives, projective tests can be difficult to score.
To ensure reliability, projective tests must be accompanied by a specific set of scoring criteria. Projective tests are more reliable and valid when scoring focuses on the way the questions are answered (sturcdture of responses) rather than the content of the answers.
Two leading projective tests are the Rorschach and the Thematic Apperception Test(TAT).
b. The Rorschach Test
In the Rorschach, individuals are asked to describe in detail their impressions of a series of inkblots. Scoring involves analysis of both the structure and content of responses.
c. The Thematic Apperception Test (TAT)
In the TAT, individuals construct stories to describe a series of pictures. TAT analysis traditionally focuses on the role played by the main character in each story.
5. Specific clinical tests attempt to measure specific clinical matters, such as your current level of anxiety or depression.