Students choose any laboratory in the program, or, where appropriate, in the University, for each of three rotations. Second year students share their rotation experiences at the end of each semester. Faculty talks, at the biennial retreat and in year first courses, and consultations with co-directors also help inform rotation decisions. Rotations are initiated by students according to individual interests and last one semester. The duration can sometimes be shorter or longer as determined by consultation between the student, the rotation supervisor, and the advisor. Students are strongly encouraged to do three rotations; however, the third rotation is occasionally waived for students with extensive research experience. A fourth rotation may be included under exceptional circumstances.

The goals of a laboratory rotation are to ensure that students learn technical skills and are made aware of the larger theoretical issues addressed by the research program. This happens through reading, participation in lab meetings and mentoring. At the end of each rotation, faculty members fills out a written evaluation providing a grade and comments about the student performance. Students provide written evaluations of rotation experiences to the program advisors prior to advisory meetings.