Criterion-referenced evaluation (CRE) describes achievement in performance terms, whereas norm-referenced evaluation (NRE) compares the performance of one individual to that of others with respect to a given evaluation instrument. Vocational educators who base their programs on behaviorism commonly evaluate student performance from a CRE perspective. When deciding whether to use CRE or NRE to evaluate a given instance of learning, vocational instructors must examine their purposes in undertaking the given evaluation. In situations when an individual's performance must be measured in terms of comparison with a standardized sample, NRE is the obvious choice. However, vocational educators must also realize the value of CRE in assessing the effectiveness of given instructional treatments in achieving specific instructional objectives. (MN)