This study examined the appropriateness of the use of criterion referenced tests as a means of controlling an individual student's advancement to the next level of instruction or retention in the current unit in the PLATO Air Force Base Computer-Based Education project at Chanute. The study was also concerned with program evaluation, which requires the establishment of a criterion rate for validation of a lesson, so that a lesson would be considered validated if the percentage of failure rate at the end of the lesson were less than the criterion. (CMV)