Guide to This Edition

This edition of Projections of Education Statistics to 2011 provides projections for key education statistics, including enrollment, graduates, teachers, and expenditures in elementary and secondary schools and enrollment and graduates of degree-granting institutions. Current-fund expenditures of degree-granting institutions are excluded from this edition because of lack of available data for recent years. The tables, figures, and text contain national data on enrollment, teachers, graduates, and expenditures for the past 14 years and projections to the year 2011. The tables, figures, and text contain state-level data on projections of public school elementary and secondary enrollment and public high school graduates to the year 2011. Similar methodologies were used to obtain a uniform set of projections for 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 appearing in this report. These projections reflect 1999 population estimates and population projections based on the 1990 census, but are not adjusted for the 1990 net undercount of 4 to 5 million. The population projections are not based on the 2000 census data. Projections of national population data are not scheduled for release until 2002. Appendix A describes the methodology and assumptions used to develop the projections. Appendix B contains tables of supplementary data. Data sources are presented in appendix C. Appendix D is a glossary of terms. Appendix E describes the survey methodology of the 1999 Integrated Postsecondary Education Data System (Fall Enrollment).

Limitations of Projections

Projections of time series usually differ from the final reported data due to errors from many sources. This is because of the inherent nature of the statistical universe from which the basic data are obtained and the properties of 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. These alternatives are not statistical confidence limits, but instead represent judgments made by the authors as to reasonable upper and lower bounds. 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 K-12 for lead times of 1, 2, 5, and 10 years were 0.2, 0.5, 1.2, and 2.9 percent, respectively. On the other hand, mean absolute percentage errors for doctor's degrees for lead times of 1, 2, and 5 years were 2.0, 2.8, and 3.7 percent respectively. For more information on mean absolute percentage errors, see table A2.

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.

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