Replication Data for: Voluntary Practice Tests improve Exam Performance: Evidence from an Introductory Economics Cours

Striking the right balance between mandatory requirements and voluntary practice opportunities is a universal challenge for teachers. While voluntary practice tests offer a way for students to self-calibrate effort, their effectiveness is difficult to assess because participation is endogenously selected. We address this challenge using quasi-experimental methods in a German university setting where voluntary practice tests are rewarded with bonus points on the final exam but are not mandatory. We find that incentivized voluntary testing increases final-exam performance by 11–17%, with no evidence of negative spillovers to performance in other same-semester courses. Using an honest causal forest, we further document substantial treatment-effect heterogeneity, with the largest gains among mid-performing students. Overall, we contribute methodologically with placebo-validated causal estimates in a highly endogenous setting, and policy-wise by showing that modest incentives for voluntary testing can yield sizable learning improvements.