The Two Most Useful Approaches to Estimating Criterion‐Referenced Test Reliability in a Single Test Administration

In criterion‐referenced tests (CRTs), the traditional measures of reliability used in norm‐referenced tests (NRTs) have often proved problematic because of NRT assumptions of one underlying ability or competency and of variance in the distribution of scores. CRTs, by contrast, are likely to be created when mastery of the skill or knowledge by all or most all test takers is expected and thus little variation in the scores is expected. A comprehensive CRT often measures a number of discrete tasks that may not represent a single unifying ability or competence. Hence, CRTs theoretically violate the two most essential assumptions of classic NRT re liability theory and they have traditionally required the logistical problems of multiple test administrations to the same test takers to estimate reliability. A review of the literature categorizes approaches to reliability for CRTs into two classes: estimates sensitive to all measures of error and estimates of consistency in test outcome. For single test administration of CRTs Livingston's k²is recommended for estimating all measures of error, S_c is proposed for estimates of consistency in test outcome. Both approaches compared using data from a CRT exam and recommendations for interpretation and use are proposed.