In-course assessment, such as midterms, quizzes or presentations, is often an integral part of higher education courses. These so-called intermediate assessments influence students' final grades. The current review investigates which characteristics of intermediate assessment relate to these grades. In total, 88 articles were reviewed that examined the relationship between intermediate assessment and student grades. Four main characteristics were identified: the use of feedback, whether the assessment is mandatory, who is the assessor, and the reward students get for participating. Results indicate that corrective feedback leads to the most positive results, but elaborate feedback may benefit lower achieving groups. No difference in results was found for mandatory versus voluntary intermediate assessments. Peer assessment seemed to be beneficial, and rewarding students with course credit improves grades more than other rewards. Three scenarios are presented on how teachers can combine the different characteristics to optimise their intermediate assessment.