This report examines the limitations of research that has been conducted on the effects of retention and social promotion. It reexamines seven research studies that provide strong evidence based on strong methodology that includes the following three characteristics: (1) the studies identify the basis of comparison, that is, whether they are comparing the achievement of retained versus promoted students at the same age or same grade level; (2) the studies identify the specific kind of educational program that students receive after either retention or promotion; and (3) the studies examine the long-term effects of retention and promotion. It is concluded that neither retention nor social promotion is a satisfactory response to the need to provide appropriate instruction for low performing students. Two tables present summaries of the studies and their effect sizes. A 29-item list of references is included. (Author/SLD)