This edition of Projections of Education Statistics provides projections for key education statistics, including enrollment, graduates, teachers, and expenditures in elementary and secondary schools. Included are national data on enrollment and graduates for the past 15 years and projections to the year 2018, as well as state-level data on enrollment in public elementary and secondary schools and public high school graduates to the year 2018.
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. The projections of public and private elementary and secondary school enrollment do not include projections of the number of students who will be homeschooled 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. Therefore, alternative projections are shown for most statistical series to denote the uncertainty involved in making projections. The low and high alternative projections are not statistical confidence limits. They are based on alternative forecasts of economic variables produced by the economic consulting firm IHS Global Insight and incorporate an adjustment that takes into account past forecast errors.
The mean absolute percentage error is one way to express the forecast accuracy of past projections. This measure expresses the average value of the absolute value of errors in percentage terms. For example, the mean absolute percentage errors of public school enrollment in grades PK–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 bachelorís degrees for lead times of 1, 2, 5, and 10 years were 0.9, 1.9, 6.0, and 13.5 percent, respectively. For more information on mean absolute percentage errors, see table A-2 in appendix A.
Alternative projections are presented for enrollment in degree-granting institutions, earned degrees conferred, elementary and secondary teachers, and expenditures of public elementary and secondary schools.