Background Exams in anatomy courses are traditionally summative. Formative testing induces retrieval practice, provides feedback and enhances learning results. We investigated the optimal frequency for retrieval practice during an anatomy course.

Method During a first-year course, students were offered four online daily quizzes a week that assessed thoracic anatomy. Once a week they received a quiz about abdominal anatomy. Students immediately received feedback afterwards. In the fourth course week, a survey about participation and satisfaction was taken. 424 students participated in the final summative exam. Trunk wall questions were used as a control. Relationship between participation and test results was investigated with a one-way ANOVA.

Results More frequent participation in formative tests was correlated to higher scores in the summative exam with no difference between daily and weekly quizzes. This effect was found for thorax-abdomen and ‘control’ trunk wall questions. Participation in weekly quizzes was higher (p < 0.001). All survey responses showed a significant difference in favour of the weekly quiz (p < 0.001).

Discussion and conclusion Participation in formative quizzes was correlated to summative exam scores. This correlation was not specific for the material tested, probably because of diligence. Student participation and preference were much higher in weekly quizzes.