The purpose of this paper is two-fold: first, to summarize the deficiencies of data available on summer schools; and second, to provide a context for analyzing and interpreting the results from the several evaluations that do exist. The paper also reviews the studies that have been completed on summer schools and takes a closer look at the following four programs: (1) Head Start; (2) Chapter 1 Regular (i.e., programs for regular term students served by the Education Consolidation and Improvement Act of 1981); (3) Chapter 1 Migrant; and (4) Programs for the Handicapped. On the whole, there is little information on existing summer school programs. This absence of appropriate comparisons means the following is lacking: information on how compensatory education programs change the educational context, and a valid model of learning rates over time. The best evidence that does exist on the effectiveness of summer programs suggest that they are not unequivocally successful. The two major problems tend to be that the programs are short, voluntary half-day interventions with little semblance to regular programs; and that there are no clear criteria for effectiveness. Two graphs demonstrating student improvement and 79 references are included. (PS)