Characteristics of Psychological Tests Standardization Norms Raw Score

Characteristics of Psychological Tests Standardization, Norms, Raw Score, Percentile Score, Reliability, and Validity

Psychological Testing • Have you ever been given an intelligence test? • If so, do you believe it accurately measured your intelligence?

Psychological Testing • Imagine that you are a seven-year old child taking an intelligence test, and you come to the following question: “Which one of the following tells you the temperature? ” Below the question are pictures of the sun, a radio, a thermometer, and a pair of mittens. Is thermometer the only correct answer?

Psychological Testing • Suppose there are no thermometers in your home, but you often hear the temperature being given on radio weather reports. Or imagine, that you “estimate” the temperature each morning by standing outside to feel the sun’s strength, or that you know it’s cold outside when your parents tell you to wear your mittens. According to your experiences, any one of the answers to the question might be appropriate.

Psychological Testing • Your predisposition to respond to this hypothetical test question based on your experiences illustrates the complexity of intelligence test development. • A test is a standardized device for examining a person’s response to specific stimuli, usually questions or problems. • Would you rather be a worried genius or a joyful simpleton?

Psychological Testing • Psychologists follow an elaborate set of guidelines and procedures to make certain that their questions are properly constructed. 1. Must decide what their test will measure. 2. Needs to construct and evaluate items for the test that will give examiners a reasonable expectation that success on the test means something. 3. The test must be standardized.

Standardization • Standardization = Developing uniform procedures for administering and scoring a test and for establishing norms.

Norms • Norms = Standard of comparison for test results developed by giving the test to large, well defined groups of people.

Scores • Raw Score = Test score that has not been transformed or converted in any way. Does not tell where the test taker stands in relation to other test takers. • A raw score is seldom a true indicator of a person’s ability. For many tests, particularly intelligence tests, raw scores need to be adjusted to take into account a person’s age, gender, and grade level to ensure they are being compared to an appropriate comparison group.

Scores • Percentile Score = A score indicating what percentage of the test population obtained a lower score. • Percentile System = Ranking of test scores that indicates the ratio of scores lower and higher than a given score. • For example, someone’s percentile score is 84, then 84 percent of the people taking the test obtained a lower score than that person did.

Reliability • Reliability = A tests’ ability to yield the same or similar scores for the same individual, under similar conditions, through repeated testing. • Can you answer this riddle? ? ? What always ends everything?

To determine reliability. . . • Test-retest Reliability = Administer the same test to the same person on two or more occasions. (Different versions of the same test) • Split-half Reliability = Involves dividing a test into two parts; on a reliable test, the scores from the two halves should yield similar, if not identical, results. • Inter-scorer Reliability = Degree of agreement between persons scoring a subjective test (like an essay exam).

Validity • Validity = The ability of a test to measure only what it is supposed to measure and predict only what it is supposed to predict. • If a psychology exam included questions such as “What is the square root of 647? ” and “Who wrote The Grapes of Wrath? ” it would not be a valid measure of your knowledge of psychology.

Intelligence Quotients • Binet coined the phrase mental age, meaning the age level at which a child is functioning cognitively, regardless of chronological age. • In the early 1900 s intelligence was measured by a simple formula: mental age ÷ chronological age × 100 = IQ