The wage premium for college graduates is substantial. Far fewer of these benefits accrue to students who complete some college (i.e., those who do not persist to graduation), and, partly for this reason, colleges often adopt programs aimed at helping to keep at-risk students in school. This article reports on a systematic review and meta-analysis of studies of such retention programs. The studies suggest small but potentially important effects on short-term retention rates and grades earned by program participants. Studies of more comprehensive interventions using relatively more appropriate comparison groups suggested more effective results than did studies that used weaker interventions, relatively less appropriate comparison groups, or both. Even the best studies included in this review are methodologically suspect and as such do not provide a very strong basis for making policy recommendations. From a public policy perspective, this review points to the need for more investment in rigorous studies that investigate, at a finer level of detail, the specific aspects of programs that are associated with program success. Rigorous studies are also needed that investigate the interaction between programs and student characteristics to determine what types of programs are most effective for which students. (Contains 3 tables.)