This review focuses on three outcome domains: staying in school, progressing in school, and completing school. As of September 2008, What Works Clearinghouse (WWC) looked at 84 studies of 22 dropout prevention interventions that qualified for review. Of these, 23 studies of 16 interventions meet WWC evidence standards: 11 without reservations and 12 with reservations. The six other interventions have no studies that meet WWC eligibility or evidence screens. Each dropout prevention intervention that had at least one study meeting WWC standards (with or without reservations) received a rating of effectiveness in one or more of the three outcome domains: staying in school, progressing in school, and completing school. Six appendixes are included: (1) Extent of Evidence: (2) Targeted Population; (3) Characteristics of Interventions; (4) Summary of Statistically Significant of Substantively Important Positive Findings: (5) Methodology; and (6) References. (Contains 2 footnotes, 3 figures and 5 tables.) [For a related Topic Report (2007), see ED497618.]