A mixed modal study was conducted that compared the results of Mississippi Biology subject area mean scores of students that used 4X4 block, A/B block, and traditional year-long schedules in large, medium, and small-sized schools. This research also explored data about whether schedule configurations allow sufficient time for students to construct knowledge. Interviews were conducted with secondary administrators and teachers concerning the type of schedule configuration used and the influence that the schedule has on student academic performance on the Biology subject area test. The study used a quasi-comparative method for the quantitative portion of the study and a constant comparative method for the qualitative portion to explore the relationship of schedule configuration on student academic achievement on the Biology subject area test. The selected student scores indicated that the Mississippi Biology Subject Area test when used as a measure of student performance revealed no significant different on student achievement for the three school schedule configurations. Adjustment for initial differences of gender, minority status, and school size on each schedule configuration were made. Results suggest that schools may use various schedule configurations and still expect student performance on the Biology subject area test to be unaffected. However, many areas of concern were identified in the interviews that might have an impact on school learning environments. These relate to classroom management, the active involvement of students in learning, the adequacy of teacher education programs, and the stress of testing on everyone involved in high stakes testing. (Contains 31 references.) (SLD)