Current expenditures for public elementary and secondary education are projected to increase 22 percent in constant dollars between school years 2007–08, the last year of actual data, and 2020–21.
The projections of current expenditures are related to projections of economic growth as measured by disposable income per capita and assistance by state governments to local governments. For more details, see appendixes A.0 and A.4.
Many factors that may affect future school expenditures were not considered in the production of these projections. Such factors include policy initiatives as well as potential changes in the age distribution of elementary and secondary teachers as older teachers retire and are replaced by younger teachers.
Throughout this section, projections of current expenditures are presented in constant 2008–09 dollars. The reference tables, later in this report, present these data both in constant 2008–09 dollars and in current dollars. The projections were developed in constant dollars and then placed in current dollars using projections for the Consumer Price Index (CPI) (table B-6 in appendix B).
An analysis of projection errors from similar models used in the past 20 editions of Projections of Education Statistics that contained expenditure projections indicates that mean absolute percentage errors (MAPEs) for current expenditures in constant dollars were 1.3 percent for 1 year out, 2.0 percent for 2 years out, 2.6 percent for 5 years out, and 4.1 percent for 10 years out. MAPEs for current expenditures per pupil in fall enrollment in current dollars were 1.3 percent for 1 year out, 2.0 percent for 2 years out, 3.0 percent for 5 years out, and 5.5 percent for 10 years out. See appendix A for further discussion of the accuracy of recent projections of current expenditures, and see table A-2, appendix A for the mean absolute percentage errors (MAPEs) of these projections.