The use of standardized tests to evaluate the current performance of a person in some defined domain of cognitive, psychomotor, or physical functioning. A test to evaluate the extent of knowledge or skill attained by a test taker in a content domain in which the test taker had received instruction. Thus, if children 10 years and 6 months of age have a median score of 17 on a test, the score 17 is said to have an age equivalent of 10-6 for that population. Two or more versions of a test that are considered interchangeable, in that they measure the same constructs in the same ways, are intended for the same purposes, and are administered using the same directions.
Alternate forms is a generic term used to refer to any of three categories.
Parallel forms have equal raw score means, equal standard deviations, equal error structures, and equal correlations with other measures for any given population. Equivalent forms do not have the statistical similarity of parallel forms, but the dissimilarities in raw score statistics are compensated for in the conversions to derived scores or in form-specific norm tables. Comparable forms are highly similar in content, but the degree of statistical similarity has not been demonstrated. In some instances, scores on the separate dimensions may also be used in interpreting performance. See holistic scoring .