This report is designed to help Pennsylvania policymakers compare two current school reform ideas that are intended to improve student achievement: private school vouchers and class size reduction. It begins with a brief history of educational vouchers, then reviews the achievement effects of the Milwaukee, Wisconsin, and Cleveland, Ohio, educational voucher programs. The reported benefits of these programs are compared to the benefits of reducing class size in grades K-3, using data from studies on class size conducted in Tennessee, Indiana, Nevada, California, and Wisconsin. The report concludes with policy recommendations for Pennsylvania based on evidence which indicates that small classes generate the greatest gains in kindergarten and grade 1. These recommendations include providing universal, publicly funded, full-day kindergarten with student-teacher ratios of 15:1; reducing class size in first grade to 15 students; and implementing an experimental program of class size reductions in grades 2 and 3 in which class size reductions are achieved in a variety of ways. (Contains 142 references.) (SM)