Because Coleman et al. argued that the influence of school factors on the academic achievement of students was low, humerous subsequent studies have focused on examining school effectiveness. The findings of these studies were not coherent because of the limitation of disregarding the hierarchical data structure of schools. To reexamine the conclusion presented by Coleman et al., this study applied Taitung Educational Panel Survey data in three-level hierarchical linear modeling. The results reveal that, although the variance in the academic achievement of students among schools was low according to Coleman et al., the variance among homeroom classes was high, which contradicts their conclusion. This current study indicated that class factors, such as average socioeconomic status in class, and the ethnic and human capital of homeroom teachers, substantially influence the academic achievement of students. Regarding school factors, the human capital of homeroom teachers affects the academic achievement of students and is key to school effectiveness.