Logically a relation is expected between time spent on individual study and achievement. The purpose of this study is to examine whether a positive relation exists between the amount of time spent on individual study and academic achievement and whether this differs when using a test measuring short-term knowledge or one measuring long-term knowledge. Data were collected in a problem-based medical curriculum. The results suggest that time spent on individual study correlates poorly with scores on the test measuring short-term knowledge but also with those on the test measuring long-term knowledge. This study reaffirms the complexity of the relationship and it demonstrates the importance to search for qualitative factors about the way students learn.