For the last 10 years, the Duval County School System (Jacksonville, Florida) has accumulated extensive student performance data with its district-wide criterion referenced testing program (the Essential Skills Test for K-6 students and the Minimum Level Skills Test for grades 7-12), which tests over 100,000 students yearly. The research project summarized in this report analyzed the testing data to identify students' academic strengths and weaknesses, determine what grade levels and areas experience a breakdown in understanding, and discover what the county can do to increase mastery of essential concepts. Duvall County used its own curriculum objectives guides to create the STRANDS model, a mechanism that follows students' mastery of essential skills objectives in the elementary grades and their subject area mastery in the secondary grades. Using flowchart analysis techniques, the research team could plot the percentage of students passing all objectives at all levels. STRAND has helped the district narrow its focus considerably. The flowchart analysis has helped the district provide intervention strategies for students with low reading comprehension scores, compare students from different demographic groups, and improve teaching and instructional strategies. Two flowcharts (for 1988 and 1989) are included. (MLH)