In this study, four years of formal observations of classroom teaching practice were employed to ascertain the practice fidelity of a site-based school reform in a secondary school setting. Those observations were then used as a criterion variable in an examination of differences in the perspectives of administrators, teachers and teaching peers about the reform's implementation. The results showed sustained levels of practice fidelity and statistically significant differences in the ratings of administrators, teachers and peers although those differences reduced overall as the reform progressed. The perspective of administrators was the best predictor of classroom practice in the first three years of the reform although less so in the latter year when teacher and peer responses became better predictors. The implications of the findings are discussed as they relate to the practice fidelity and evaluation of site-based school reform. (Contains 6 tables and 1 figure.)