This methodological report describes in five chapters the techniques and assumptions that underlie and greatly influence the projections shown in the first volume of "Projections of Education Statistics to 1990-91." Chapter 1 describes the general methodology and assumptions used to produce the projections in Volume I. Chapters 2 through 5 provide specific information on the methodology and assumptions used to produce the projections for each corresponding chapter of Volume I. Each of these chapters contains the following information: (1) a description of the basic methodology; (2) tables of projection equations and related statistics; (3) tables of percentages and rates used to make projections; (4) a table of basic assumptions underlying the projections; and (5) a table describing the methods used to estimate missing data items. The report's appendix contains tables of economic and demographic time-series data that were also used to produce the projections in Volume I. (Author/MLF)