Standardization and Norms
STEP 4 Review the Knowledge You Need to Score High
Psychometrics is the measurement of mental traits, abilities, and processes. Psychometricians are involved in test development in order to measure some construct or behavior that distinguishes people. Constructs are ideas that help summarize a group of related phenomena or objects; they are hypothetical abstractions related to behavior and defined by groups of objects or events. For example, we can’t measure happiness, honesty, or intelligence in feet or meters. If someone tells the truth in a wide variety of situations, however, we might consider that person honest. Although we cannot observe happiness, honesty, or intelligence directly, they are useful concepts for understanding, describing, and predicting behavior. Psychological tests include tests of abilities, interests, creativity, personality, and intelligence. A good test is standardized, reliable, and valid. After many questions for a test have been written, edited, and pretested, questions are thrown out if nearly everyone answers them correctly or if very few answer them right because these types of questions do not tell us anything about individual differences. Tests that differentiate among test takers and that are composed of questions that fairly test all aspects of the behavior to be assessed are assembled. They are then administered to a sample of hundreds or thousands of people who fairly represent all of the people who are likely to take the test. This sample is used to standardize the test. Standardization is a two-part test development procedure that first establishes test norms from the test results of the large representative sample that initially took the test and then ensures that the test is both administered and scored uniformly for all test takers. Norms are scores established from the test results of the representative sample, which are then used as a standard for assessing the performances of subsequent test takers; more simply, norms are standards used to compare scores of test takers. For example, the mean score for the SAT is 500 and the standard deviation is 100, whereas the mean score for the Wechsler Adult Intelligence Scale (IQ test) is 100 and the standard deviation is 15, based on the “standardization” sample. When administering a standardized test, all proctors must give the same directions and time limits and provide the same conditions as all other proctors. All scorers must use the same scoring system, applying the same standards to rate responses as all other scorers. Thus, we should earn the same test score no matter where we take the test or who scores it.