Mastery Learning in Practice: A (Mostly) Descriptive Analysis of Log Data from the Cognitive Tutor Algebra I Effectiveness Trial

Abstract: Mastery learning, the notion that students learn best if they move on from studying a topic only after having demonstrated mastery, sits at the foundation of the theory of intelligent tutoring. This paper is an exploration of how mastery learning plays out in practice, based on log data from a large randomized effectiveness trial of the Cognitive Tutor Algebra I (CTAI) curriculum. We find that students frequently progressed from CTAI sections they were working on without demonstrating mastery and worked units out of order. Moreover, these behaviors were substantially more common in the second year of the study, in which the CTAI effect was significantly larger. We explore the various ways students departed from the official CTAI curriculum, focusing on heterogeneity between years, states, schools, and students. The paper concludes with an observational study of the effect on post-test scores of teachers reassigning students out of their current sections before they mastered the requisite skills, finding that reassignment appears to lowers posttest scores--a finding that is fairly resilient to confounding from omitted covariates--but that the effect varies substantially between classrooms.