An across-groups (classrooms), multiple-baseline design was used to investigate the effects of an interdependent group-oriented contingency on the Accelerated Reader (AR) performance of fourth-grade students. A total of 32 students in three classes participated. Before the study began, an independent group-oriented reward program was being applied (i.e., a student received access to a tangible reward after passing each AR comprehension test). This program was supplemented with an interdependent group-oriented contingency, and results showed that the number of quizzes passed per week increased immediately after the intervention was applied; however, this increase was not maintained. When students were divided into ability groups based on their average baseline performance, the lowest performing students exhibited a statistically significant increase in quiz performance (i.e., quizzes taken, quizzes passed, and book level), but no significant changes were found in the average and high performing groups
