Using a cooperative learning framework in a quantitative reasoning laboratory course, students were assigned to static teams of four in which they adopted roles that rotated regularly. The roles included: team leader, protocol manager, data recorder, and researcher. Using a mixed-methods approach, we investigated students' perceptions of the team roles and specifically addressed students' understanding of the roles, students' beliefs in their ability to enact the roles, and whether working with assigned team roles supported the teams to work effectively and cohesively. Although students expressed confidence in their understanding of the team roles, their understanding differed from the initial descriptions. This suggests that students' understanding of team roles may be influenced by a variety of factors, including their experiences within their teams. Students also reported that some roles appeared to lack a purpose, implying that for roles to be successful, they must have a clear purpose. Finally, the fact that many students reported ignoring the team roles suggests that students do not perceive roles as a requirement for team productivity and cohesion. On the basis of these findings, we provide recommendations for instructors wishing to establish a classroom group laboratory environment.