Reported is a study to compare the achievement of selected 10th-grade biology students on a traditional schedule with selected 10th-grade biology students on a flexible modular schedule. Both groups studied the blue version of the Biological Sciences Curriculum Study (BSCS) materials. Students were paired in the groups on the basis of their scores on Test 2, Background in Natural Sciences, and the composite of the Iowa Tests of Educational Development. Achievement was measured by use of the BSCS Comprehensive Final Examination for first year biology students. Additional data came from scores on the Brown-Holtzman Survey of Study Habits. Twenty-nine matched pairs of students were involved in the final data analysis. No significant differences were found in achievement; in study habits, study attitudes, and study orientation; nor did school organizational type affect student achievement in BSCS biology. (Author/PEB)