This model is a computerized mathematical simulation of the manner in which educational decisions and patterns of school operation affect costs. The design shows how teacher salaries, school building design parameters, and decisions regarding class size and instructional materials expenditures contribute to total school costs. The sophisticated economic analysis provided by the COST-ED model is especially useful in program evaluations, program budgeting, and program simulations. Appendixes present sample computer reports and a glossary of terms. (Author/RA)