Limited to a comparison of one open school and one traditional school, this study was performed to empirically assess the claims of open classroom proponents. Approximately 250 students in grades 1 through 6 of two elementary schools, one utilizing an open classroom instructional program and the other a traditional instructional program, comprised the sample in the two-year study which focused on the assessment of the comparative effects of the two instructional programs upon three student variables: (1) self-concept, (2) attitude toward school, and (3) achievement of basic skills. Measurement of these variables were accomplished by the use of the Piers-Harris Self-Concept Scale and the Pictorial Self-Concept Scale, the "Faces" Inventory, and the Stanford Achievement Test. Pretests on the three variables were administered in May and June of 1972; posttests were administered in May and June of 1974. Analysis of covariance was used to analyze this data. In addition, data related to teacher attitudes and classroom environment and practices was collected and analyzed. Results do not provide support for any conclusive comprehensive statements concerning the relative effectiveness of the open or traditional instructional program. However, there was evidence to suggest that the open classroom instructional program effected positive changes in the affective areas of self-concept and attitude toward school. Students in both instructional programs performed equally well in the achievement of basic skills. (Author/RC)