Total enrollment is projected using expected progression rates and college enrollment rates drawn from institutional data from the National Center for Education Statistics (NCES); demographic data and population projections from the U.S. Census Bureau; and historical and projected economic data from Standard and Poor's, Inc. Grade progression rate (cohort survival), exponential smoothing, and multiple linear regression are the major projection techniques used to forecast these rates.

For school enrollment, the grade progression rates were projected using exponential smoothing. State-level public school enrollment projections also were based on the grade progression. Individual state governments produce projections based on additional or alternative factors which may lead to more accurate projections for their own state. The NCES state projections program is designed to use a consistent model for all states that enables state-to-state comparisons.

For college enrollment, the age-specific enrollment rates were projected using econometric models by taking into account the effects of demographic changes and economic conditions. For graduates of public high schools by state, projections were developed on the basis of grade 12 enrollment.

Demographic assumptions used by NCES are consistent with U.S. Census Bureau middle series of population projections which assumes a fertility rate of 2.12 births per woman by the year 2010, an annual net immigration from 960,000 to 720,000 per year, and a further reduction in the mortality rate. Economic assumptions for disposable income and unemployment rates are consistent with Standard and Poor's Inc. trend forecast scenario.

For more information on the methodological details of the assumptions and methods used to develop these projections, and details on data sources, see Projections of Education Statistics to 2010, pages 113 through 128.