This edition of Projections of Education Statistics provides projections for key education statistics, including enrollment, graduates, teachers, and expenditures in elementary and secondary public and private schools. Included are national data on enrollment and graduates for the past 15 years and projections to the year 2019. Also included are state-level data on enrollment in public elementary and secondary schools and public high schools from year 2001 and projections to year 2019. This report is organized by the level of schooling with sections 1, 2, 3, and 4 concerned with aspects of elementary and secondary education and sections 5 and 6 concerned with aspects of postsecondary education.
State-level data on enrollment and graduates in private schools are not included. Further research and model development are needed to develop reliable projections of private school enrollment and graduates by state. Neither the actual numbers nor the projections of public and private elementary and secondary school enrollment include homeschooled students because more data are required to develop reliable projections.
Similar methodologies were used to obtain a uniform set of projections for each of the 50 states and the District of Columbia. These projections are further adjusted to agree with the national projections of public elementary and secondary school enrollment and public high school graduates contained in this report.
The summary of projections provides highlights of the national and state data, while the reference tables and figures present more detail. All calculations within the Projections of Education Statistics are based on unrounded estimates. Therefore, the reader may find that a calculation, such as a difference or percentage change, cited in the text or figure may not be identical to the calculation obtained by using the rounded values shown in the accompanying tables.
Appendix A describes the methodology and assumptions used to develop the projections; appendix B presents supplementary tables; appendix C describes data sources; appendix D is a list of abbreviations; appendix E presents the references; and appendix F is a glossary of terms.
Projections of a time series usually differ from the final reported data due to errors from many sources, such as the properties of the projection methodologies, which depend on the validity of many assumptions.
The mean absolute percentage error is one way to express the forecast accuracy of past projections. This measure expresses the average of the absolute values of errors in percentage terms, where errors are the differences between past projections and actual data. For example, the mean absolute percentage errors of public school enrollment in grades prekindergarten–12 for lead times of 1, 2, 5, and 10 years were 0.3, 0.6, 1.3, and 2.3 percent, respectively. In contrast, mean absolute percentage errors for bachelor’s degrees for lead times of 1, 2, 5, and 10 years were 0.8, 1.8, 5.9, and 13.6 percent, respectively. For more information on mean absolute percentage errors, see table A-2 in appendix A.