The paradox of site-based school management with use of standardized tests or instructional management systems that restrict teacher choices was evident in one school district in North Carolina in which measurement of student success has centered on student performance on state-mandated tests. A study was conducted to see if students whose teachers were part of the Gaston County (North Carolina) instructional management system for mathematics and communication skills (MAC)--a criterion referenced test-based system--scored higher on the California Achievement Test (CAT) than students whose teachers were not part of the MAC program. Subjects were 949 MAC sixth graders, with a control group of 1,306 non-MAC students. Data were collected from the 1988-89 administrations of the CAT. Students whose teachers used the MAC program did not outperform non-MAC students in any respect. In addition, male students in the MAC program consistently scored lower than did male students not in the MAC program and scored significantly lower than did female students in the MAC program. The attempt to improve test scores through the MAC program has not been successful. Recommendations are made for a complete evaluation of the MAC program. (SLD)