Universities around the world use tutorials to personalize the education of the student. Given that tutorials are costly and poorly attended, should students be forced to attend? We use data from a large European University to investigate the impact of forced attendance on student performance. We exploit the fact that students were forced to go to second year tutorials if their first year grade point average was below a minimum requirement. We show that the requirement increased second-year attendance by about 25 percentage points (over a baseline of about 65 percent). In turn, a 10 percentage point increase in forced attendance decreases student performance by 0.1 standard deviations. We then turn to investigating why there is this decrease in student performance. We show that forced attendance makes students more confident about the course material. In turn they spend less time studying on their own. The results suggest forced attendance decreases student performance because tutorials are used as a substitute for, rather than a complement to, self study.