Despite mixed reviews from many educators--and some researchers--Chicago's retention policy to end social promotion has turned out to be a popular program. Surprisingly, perhaps, its most avid fans are the people most affected by it: teachers and students. Chicago's ending of social promotion was intended to make educators pay more attention to the lowest-performing students, encourage parents to become more involved in their children's education, and send strong messages to students that achievement mattered. Fortunately, the Chicago experiment--now in its eighth year--became part of an ongoing study of the city's public school system begun by the Consortium on Chicago School Research (CCSR) in 1994. Since 1999 the CCSR has published several studies of Chicago's attempt to end social promotion that helps to provide an extensive, empirical, and longitudinal look at the impact of the high-stakes testing policies on the Chicago school system. This article is adapted from one of those reports, "Ending Social Promotion: Response of Students and Teachers." The study drew on four basic sources of data: teacher surveys, principal surveys, student surveys, and personal interviews with a sample of teachers from five low-performing schools. Overall, though the study confirms some of the fears expressed by opponents of the program, the student and teacher survey responses and personal interviews also suggest that Chicago's bold experiment had a positive impact. Although time spent on test preparation increased substantially after the institution of high-stakes accountability, it declined in subsequent years. Teachers shifted instructional emphases in reading and math, increasing student exposure to grade-level material, and devoted more time to reading skills relevant to the test. Low-achieving 6th- and 8th-grade students received greater academic support and reported greater academic engagement. (Contains 3 figures.)