Characteristics of Psychology Tests Objectives: Identify 3 ways of measuring reliability. Explain test standardization Explain how test validity is assessed Vocabulary: Reliability Validity Percentile system Norms

Characteristics of Psychological Test They all try to make it possible to find out a great deal about a person in a short period of time. They try to make predictions about: Career interest Individual desires, interests, and attitudes Reveal psychological problems They can show how an individual compares to others. They can help people understand things about themselves more clearly

Limitations of Psychological Tests We tend to forget that test are merely tools for measuring and predicting human behavior. Test results are not an end in unto itself. Using test to make decisions about something needs to be the more fair and accurate measure than other criteria Fairness and usefulness depends on: Reliability Validity Standardization

Test Reliability Definition: Refers to a test’s consistency Does the test have the ability to yield the same result under a variety of similar circumstances? Test-retest reliability Interscorer reliability Scorer reliability Split-half reliability

Test-Retest Reliability If the person retakes the test or takes a similar test within a short period of time, do they receive approximately the same score?

Interscorer Reliability Does the test yield the same results when scored at different times by different people?

Scorer Reliability If the same teacher grades papers at different times, does he or she score the same paper differently?

Split-Half Reliability Randomly divide the test in half and score each separately. The two scores should be approximately the same. It should not have sections on which the person scores high and others on which he or she scores low.

Test Validity Definition: The ability of a test to measure what it is intended to measure. Does the test measure what it is supposed to? What is the purpose of the test? One of the chief methods is to find out how well a test predicts performance. Predictive Validity

Standardization Criteria: Standardized test must be administered and scored the same way every time. Established norms are used that have been based on the scores of a large group of people.

Establishing Norms Transfers a raw score into a percentile system, which resembles a bell curve. Place the scores in order from the highest to the lowest. Percentiles are assigned according to the percentage of scores that fall above or below the mean. The percentiles established from the test by the large test group are called the norm. Norms only refer to what has found to be the average for a particular group.

Things to Remember Do you think that if you took the same test again, you would receive a similar score? Does your performance on the test reflect your usual performance in the subject? If you were to compare your score with those of your classmates, would it reflect your general standing within the group?