Background: It has been asserted that assessment can and should be used to drive students' learning. In the current study, we present a cumulative assessment program in which test planning, repeated testing and compensation are combined in order to influence study effort. The program is aimed at helping initially low-scoring students improve their performance during a module, without impairing initially high-scoring students' performance. We used performance as a proxy for study effort and investigated whether the program worked as intended.Methods: We analysed students' test scores in two second-year (n = 494 and n = 436) and two third-year modules (n = 383 and n = 345) in which cumulative assessment was applied. We used t-tests to compare...