Data from the 1990 National Assessment of Educational Progress (NAEP) Trial State Assessment (TSA) in mathematics were analyzed to determine what educational factors influence student learning, how these factors influence learning, and how important these factors are to student achievement. NAEP TSA data were collected from more than 100,000 eighth-grade students in approximately 100 schools in each of the 37 participating states. The database for the study consisted of information on teachers, administrators, and students from 3,351 schools. A modified version of the model of J. A. Centra and D. A. Potter was used to identify paths among important educational constructs using path analysis and the 1990 NAEP TSA data. Paths among characteristics of students, school conditions, and teachers; paths to behaviors of students and teachers; and paths to achievement were identified. Results confirm that student characteristics and student behavior have large impacts on student achievement. Findings further suggest that educators can influence student behavior through teacher behavior and school conditions. Efforts to improve education should focus on things the school can control through school policies and teaching strategies. Teacher content knowledge and academic emphasis are important factors through which schools can make a difference in student achievement. Eleven figures illustrate the discussion. (Contains 35 references.) (SLD)