Examination of the literature reveals considerable variation among recommendations for the optimum size of schools. Generally, levels suggested for elementary schools ranged from 300 to 800 students. Academic, psychological, and environmental factors favored smaller student bodies, whereas, economic and institutional factors favored larger. High schools received the heaviest research interest, with student population recommendations ranging from 500 to 2,000. Higher populations seemed related to greater academic achievement, partly as a result of the curricular variety made possible, and seemed preferable for economic and institutional reasons as well. While larger institutions were seen as less orderly and coherent than smaller ones, research in this area of psychological and environmental factors has not been as complete as that in the other aspects. Junior high school information proved particularly lacking, and at present recommendations can only be inferred from the studies at the high school and elementary levels. (Author/PGD)