The Schools and Staffing Survey (SASS) represents the union of three surveys by the National Center for Education Statistics (NCES), the Teacher Demand and Shortage Survey, the School and School Administrator Surveys, and the Teacher Survey. The SASS measures critical aspects of teaching supply and demand, the composition of the teacher and administrator workforce, and the status of teaching and schooling in general. The merger of the studies produces one database. SASS is designed to provide estimates to meet its analytical goals: (1) national estimates for public and private schools; (2) state estimates for public schools; (3) state/elementary, state/secondary, and national combined public school estimates; (4) detailed association estimates and grade school estimates for private schools; (5) estimates of change from 1988 to 1991 in school level characteristics; and (6) national estimates for schools with greater than 25% American Indian enrollment. This report describes the procedures used in the following areas: (1) school and teacher sample stratum allocation; (2) overlapping 1988 and 1991 SASS samples; (3) public school sample design; (4) local education agency sample design; (5) private school sample design; (6) teacher sample design (including within school teacher allocation); (7) weighting; (8) imputation; (9) variance estimation techniques; and (10) frame evaluation. Changes in the study design since the inception of the study in 1987-88 are reviewed. Twenty figures and 24 tables illustrate the study design and changes. Four appendixes describe the Common Core of Data; and explain sample reallocation, school overlap, and the effect of a population correction. (SLD)