Among the plethora of cooperative learning studies, several investigations of cooperative or group assessment (CA) have appeared. In this investigation, the methodology of R. R. McCown (1992) is refined to examine CA in a classroom setting, primarily examining achievement outcomes and student perceptions of the CA process. Fifty-six undergraduates in educational psychology participated in a nonequivalent control group design. It was hypothesized that students taking a test using a CA procedure would perform significantly better on a posttest of course concepts than would students completing the test in traditional format. The CA group completed examinations individually and in groups, while the traditional group (TA) took examinations individually. Analysis of covariance did not support the hypothesis. However, student reactions to the CA process were overwhelmingly positive. An appendix gives means, modes, and standard deviations for the group assessment survey. (Contains 13 references.) (Author/SLD)