The study determined whether students' self-recording of their class comments differed from observers' tallies of student comments and specifically whether students overreported their comments when credit was available for participation. In three sections (51-57 students per section) of an undergraduate educational psychology course, participants received a small amount of credit toward their grade for reporting up to two comments per class session in selected course units. Participants self-recorded their comments on a specially designed card on all days set aside for discussion in all units, including the noncredit units. Agreement between participant and observer records of individual participation proved high overall, and students did not overreport their comments under credit conditions.