This paper discusses criterion referenced tests' characteristics and their use in clinical evaluation. The distinction between diagnostic tests and criterion referenced measures is largely a matter of emphasis. Some authorities believe that in diagnostic testing the emphasis is upon an evaluation of an individual's strengths and weaknesses in skills areas with attention to the possible causes of problems that exist. Criterion referenced testing is less concerned with definition of disability and does not emphasize the etiology of problems. In constructing norm referenced test items, the writers of the test must select items of varying levels of difficulty. In criterion referenced measurement the scale is usually anchored at the extremes--one at the top indicating complete or perfect mastery of some defined abilities; one at the bottom indicating absence of some skills. The items on a criterion referenced measurement should be representative of skills that are essential to learning to read. The items should be arranged in an established hierarchy that would be used for teaching reading. In a clinical situation where the number of students is small, criterion referenced measures are simply ways of determining whether goals have been met. (WR)