Intending to provide school administrators with technical information to assist in preparing student enrollment projections and techniques in analyzing projections, this paper explores the state of the art, major factors affecting school populations, and the Cohort Survival Ratio Method. The authors caution that there are no absolutely reliable methods for predicting changes in enrollment, but state that the Cohort Survival Ratio Method is generally accepted as the most understandable and effective tool available. The factors greatly affecting student numbers are identified as births, migration, and holding power (dropout rate). The authors conclude that pupil population projections are essential in planning budgets, programs, and facilities and that educational planners should collect information from private, commercial, and governmental agencies. They further recommend that each administrative unit have a person responsible for making enrollment projections. (Author/WD)