Diplomas Count uses the Cumulative Promotion Index (CPI) method to calculate high school graduation rates for American public schools. This approach allows the EPE Research Center to compute the percent of public high school students who graduate on time with a diploma.
The CPI method represents the high school experience as a process rather than an event, capturing the four key steps a student must take in order to graduate: three grade-to-grade promotions (9 to 10, 10 to 11, and 11 to 12) and ultimately earning a diploma (grade 12 to graduation). Each of these individual components corresponds to a grade-promotion ratio. Multiplying these four grade-specific promotion ratios together produces the graduation rate.
Different methods for calculating a graduation rate may employ different definitions of a “graduate.” The CPI method adheres to federal guidelines, under which only students receiving standard high school diplomas count as graduates. Recipients of General Educational Development diplomas, certificates of attendance, and other nondiploma credentials are treated as nongraduates in this context. States must adopt a similar definition of a graduate for the rates they calculate to fulfill federal accountability requirements, although they may employ different definitions for other purposes.
The 2011 edition of Diplomas Count presents a new analysis of graduation rates for the high school class of 2008, the most recent year for which information is available. Data for 2008 and prior years were obtained from the U.S. Department of Education’s Common Core of Data (CCD), an annual census of all public schools and school districts in the country.
Several states—Delaware, Maine, and South Carolina—did not report either total or subgroup diploma counts to the CCD for 2007-08. The EPE Research Center obtained comparable graduation data directly from the state education agencies, where available. The center also revised certain enrollment data points using agency-reported information from the District of Columbia and Utah.
The EPE Research Center calculates graduation rates for all school districts in the country that issue diplomas (that is to say, those with a 12th grade). Statistics for the nation and states are generated by aggregating district-level data upward.
