Detailed methodology used to evaluate a causal model of school environment is presented in this report. The model depicts societal features that influence school district values and organizational characteristics, which in turn influence school operations and personnel attitudes and values. These school variables affect school community members' perceptions of school climate, which then influence student outcomes. Questionnaires were completed by 352 principals, 14,721 teachers, and 24,874 students from 362 junior and senior high schools in 36 states and Canada. Findings suggest that student and/or teacher climate variables played a significant role in all the analyses. Of the sociodemographic variables, the percentages of students receiving free lunches and the percent of minority students in the school had the largest and most consistently direct and indirect effects on the outcome variables. Most school input variables' effects on outcomes were mediated by school climate variables. The findings indicate reasonable support for Keefe's mediated (1985) model of school outcomes and constitute the basis for a comprehensive assessment of school environments and possible interventions. Seven figures and one table of final variables are included. (8 references) (LMI)