An attempt is made to consolidate some of the existing knowledge about important school variables and to propose new studies that will build upon that knowledge. The focus is on providing instruction to students from the orientation of educational psychology and in the context of elementary schools for students from low socioeconomic status groups. A tentative list of twenty variables is categorized in eight categories: time, instructional articulation, teacher characteristics, instructional integration, instructional organization, teacher/student interactions, classroom control, and instructional materials. The rationale for these variables and categories is presented, based on educational utility and research support. Procedures for measuring variables are suggested. The operation of these variables is explained with reference to a chart relating school district variables, school variables, teacher characteristics, classroom variables, student characteristics, student mental processes, and student learning outcomes. The final section discusses research strategy, generally recommending a number of comparatively small studies aimed at indicating relationships rather than testing hypotheses, and taking into account the possible complex interrelationships that may exist between variables. (Author/CTM)