Evaluations of the "Long-Range Magnet School Plan" court-ordered desegregation program occur in 3 year cycles. This report evaluates the programs of three Science and Mathematics Magnet Middle Schools in operation in Kansas City, Missouri. After presenting a program description and evaluation design, enrollment and achievement trends at the three schools during 4 years of operation are reported. Minority and non-minority students from sixth through eighth grade were examined for patterns of achievement performance on the following standardized tests: Iowa Tests of Basic Skills (ITBS), Missouri Mastery and Achievement Testing (MMAT), and Degrees of Reading Power (DRP). Two intact groups of students, enrolled continuously for 3 years, were tracked from the sixth grade to the eighth grade for patterns of achievement on the ITBS. Examination of achievement data indicated differences in achievement between minority and non-minority students in favor of non-minority students. The researchers reported that this finding supported the conclusion that the magnet program continues to impact non-minority achievement to a greater extent that minority achievement. Findings of the most recent cohort group, with the exception of reading achievement, indicated that this discrepancy may have been reduced substantially. Results from ANCOVA with a sample of district middle school students as a comparison group indicate few significant differences between math/science students and comparison students. The researchers concluded that without substantial improvement in minority achievement, the program has not completely fulfilled its' mission. (MDH)