This research compared course achievement in elementary statistics under Keller-plan Personalized Systems of Instruction and under other lecture methods of instruction incorporating only some of the basic components of Keller-plan teaching methods. The addition of content unitization and learning objectives to a lecture/midterm method resulted in course achievement below that found with Keller-plan methods. However, the addition of frequent testing (12 tests in a 14-week semester), content unitization, and learning objectives to a lecture method resulted in achievement at the same high level as achievement of students in a Keller-plan course. Both findings were replicated in two independent semesters. These results suggested that the achievement found in Keller-plan courses may be due to the frequent testing aspects of the mastery learning component of such methods and not to the personalization with proctors or allowance for individual rates present in Keller-plan methods. © 1977.
Abbott, R. D., & Falstrom, P. (1977). Frequent testing and personalized systems of instruction. Contemporary Educational Psychology, 2(3), 251–257. https://doi.org/10.1016/0361-476X(77)90027-3