The authors document the decline in high school enrollment from 1993 to 2000 and examine why it occurred. Analysis shows that the introduction of the promotion gate policy to CPS elementary schools in the 1995-96 school year had a profound effect on high school enrollment. As lower achieving eighth-grade students were retained or sent to Academic Preparatory Centers, the size of ninth-grade cohorts shrank. Successive grades were affected as smaller cohorts moved through high school. The better prepared students who did make it to ninth grade were less likely to spend more than four years in high school than in the past, thereby further depressing enrollment. As a result of this reduction in high school course repetition, the increase in eighth grade retention was not accompanied by a decline in graduation rates by age 18.

The report includes system trends of factors affecting each grade's enrollment including: 1) The size of the previous grade in the previous year; 2) the number of new students; 3) the rate of leaving CPS from the previous grade; 4) the dropout rate from the previous grade; 5) the promotion rate from the previous grade; 6) the promotion rate from this grade; 7) the grade skipping or reclassification into this grade; and 8) the skipping the current grade. It also includes a school-by-school look at changes in enrollment and system wide graphs for each year of students' progression through school starting at age thirteen.