An analysis of projection errors from the past 14 editions of Projections of Education Statistics indicates that the mean absolute percentage errors (MAPEs) for projections of classroom teachers in public elementary and secondary schools were 1.0 percent for 1 year out, 1.5 percent for 2 years out, 2.7 percent for 5 years out, and 5.4 percent for 10 years out. NCES projections of public elementary and secondary teachers produced over the last 14 years have been less accurate than NCES projections of public elementary and secondary enrollment produced over the same period. For more information on the MAPEs of different NCES projection series, see table A2 in appendix A.
