In addition, retention in a grade during the years before high school increases the likelihood that a student will drop out. The study involved a computer tracking of all newly enrolled ninth graders in the graduating classes of 1982, 1983, and 1984. More than 100,000 student records were examined longitudinally, tracking their entrance and final departure from the public school system. Dropouts were defined as all those who left without transferring to schools outside the Chicago system. The overall graduation rate was 57 percent. Dropout rates were 47 percent for Hispanics, 45 percent of blacks, 35 percent of whites, and 19 percent of Asians. Students entering high school 1 year or more above the normal age had a 60 percent dropout rate, versus 37 percent for those of normal age. Overage students were more likely to drop out even if they were reading at the same or higher level than normal-age students. Findings also indicated that the school system's emphasis on creating selective schools for the best-prepared student has become, effectively, a policy of educational triage. The relatively effective schools are either selective of their entering students or are located in solidly middle-class areas. The least well-prepared students are shunted into a few schools with the least challenging programs and with few successful peer role models. Data tables.