Section 6. Expenditures of Public Elementary and Secondary Schools: Accuracy of Projections

An analysis of projection errors from similar models used in the past 17 editions of Projections of Education Statistics that contained expenditure projections indicates that mean absolute percentage errors (MAPEs) for total current expenditures in constant dollars were 1.3 percent for 1 year out, 2.2 percent for 2 years out, 2.9 percent for 5 years out, and 3.8 percent for 10 years out. MAPEs for current expenditure per pupil in fall enrollment in current dollars were 1.3 percent for 1 year out, 2.1 percent for 2 years out, 3.3 percent for 5 years out, and 5.4 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 in appendix A for the mean absolute percentage errors (MAPEs) of these projections.