The number of high school graduates increased nationally by 32 percent between 1995–96 and 2007–08, the last year of actual data. A decrease of 3 percent is expected between 2007–08 and 2020–21. Both public schools and private schools are expected to have decreases in the number of high school graduates. Increases are expected in the West and South, and decreases are expected in the Northeast and Midwest.
The projections of high school graduates are related to projections of 12th-graders and the historical relationship between the number of 12th-graders and the number of high school graduates. The methodology implicitly includes the net effect of factors such as dropouts, transfers to and from public schools, and, at the state level, migration. For more details, see appendixes A.0 and A.2.
A high school graduate is defined as an individual who has received formal recognition from school authorities, by the granting of a diploma, for completing a prescribed course of study. This definition does not include other high school completers or high school equivalency recipients. Projected changes in the number of graduates reflect changes in the 18-year-old population over the projection period, rather than projected changes in the graduation rates of 12th-graders. Projections of graduates could be affected by changes in policies influencing graduation requirements.
For National Center for Education Statistics (NCES) projections of public high school graduates produced over the last 20 years, the mean absolute percentage errors (MAPEs) for lead times of 1, 2, 5, and 10 years out were 1.0, 1.0, 1.6, and 4.0, respectively. For NCES projections of private high school graduates produced over the last 9 years, the MAPEs for lead times of 1, 2, 5, and 10 years out were 0.9, 0.9, 5.0, and 1.6, respectively. For more information, see table A-2 in appendix A.