Within the past year, two new reports have highlighted American graduation rate statistics. While differences in focus and methodology exist between the reports, both make it clear that far fewer students are graduating from high school than almost anyone believed. In exposing a high school graduation crisis through simple statistics and straightforward methodology, both reports–Losing Our Future: How Minority Youth Are Being Left Behind by the Graduation Rate Crisis, by the Civil Rights Project at Harvard University in conjunction with the Urban Institute, Advocates for Children of New York, and the Civil Society Institute, and Public High School Graduation and College Readiness Rates in the United States, by the Manhattan Institute-contribute much to the debate over the problems that exist in American high schools and what can be done to address them.
Researchers at the Manhattan Institute calculated their graduation rates using the Greene Method, developed by Jay Greene, who coauthored the working paper with Greg Forster. The Greene Method calculates graduation rates by following one cohort of students, adjusted according to demographic statistics, over the four years of high school to graduation. The number of students in a ninth-grade class is adjusted to account for a ninth-grade “bulge” that exists because students tend to be held back relatively more often in the ninth grade, and it is adjusted again to account for changes in the size of the student population in question over the period of four years. The Greene Method then divides the number of diplomas awarded four years later by the adjusted ninth-grade number to determine a graduation rate for the population in question. In effect, the result of the Greene Method is the percentage of a ninth-grade class that successfully earns a high school diploma in four years. It estimates that the national graduation rate for all students in 2001 was 70 percent.
The report by the Civil Rights Project uses statistics developed by the Urban Institute. They refer to their method of graduation rate calculation as a Cumulative Promotion Index (CPI). The CPI, like the Greene Method, uses enrollment and diploma data from the Common Core of Data, a compilation of data from reports by individual schools and districts. Unlike the Greene Method, however, it examines data from a two-year, not a four-year, period. The CPI collects enrollment information for each high school grade, nine through twelve, in a given year. It then collects enrollment in grades ten to twelve as well the number of diplomas awarded the following year. The CPI represents the probability that a student will be promoted through school, at the rate of one grade per year, from ninth grade to graduation. The Harvard Civil Rights Project, like the Manhattan Institute, reports graduation rates for each state disaggregated by race. It also reports graduation rates for the fifty largest school districts in the country. Nationally, it estimates that the overall graduation rate for 2001 was 68 percent.
The two groups use different methodologies with different relative strengths and applications; the numbers from the Manhattan Institute more directly represent a cohort of students’ graduation rate over a period of four years, while the Urban Institute’s numbers show the likelihood of promotion from ninth grade to graduation during one particular “snapshot” year, and require only one year’s worth of data to track changes. When applied to large populations, however, both methods produce remarkably similar results. Whether the national graduation rate in 2001 was 68 percent or 70 percent is, ultimately, not very important. What is crucial is that the numbers published in both reports show a graduation crisis far larger than anything previously reported. The straightforward methodologies of both show that nearly a third of American high school students fail to graduate and that high school reform is therefore both urgent and essential.
The full text of Losing Our Future can be found at http://www.urban.org/UploadedPDF/410936_LosingOurFuture.pdf.
Public High School Graduation and College Readiness Rates in the United States is available at http://www.manhattan-institute.org/html/ewp_03.htm.