This study estimated the promotion power of public high schools in the District of Columbia. Promotion power is a measure of school effectiveness that distinguishes a school's contributions to student outcomes from the contributions of the background characteristics of the students it serves. Promotion power scores are distinct from status measures such as graduation rate and college enrollment rate because they account for prior student achievement and other student background characteristics in measuring schools' contributions. They complement value-added measures by using similar methods to examine additional, longer-term outcomes. The study found wide variation in high schools' promotion power for college-ready SAT scores, high school graduation, and college enrollment. Schools with high promotion power for high school graduation were also more likely to have high promotion power for college enrollment. Student background characteristics were less strongly related to promotion power scores than to status measures, suggesting that high schools serving differing student populations can show strong promotion power. [For the Study Snapshot, see ED614578. For the appendixes, see ED614581.]