CRT, also known as domain-referenced tests, employs a different frame of reference in test interpretation than does NRT. In this approach, a performance standard called criterion is established prior to testing to indicate mastery of the specific content domain covered by the test. A student's performance is compared to the preestablished criterion, rather than to the performance of other students. Interpretation of CRT results yield specific information regarding the student's proficiency in or mastery of the measured skills. In recent years, states have begun to develop minimum competence tests to assess students' performance, which are designed and used based on the theory of criterion-referenced measurement.