range, calling the school to assign a specific grade range, or, as a last resort, assigning a grade level of combined (both elementary and secondary levels). Missing information on school affiliation and student and teacher counts were assigned in a similar manner. After these changes, the private school sampling frame consisted of 28,490 private schools.
Private schools were stratified by affiliation, grade level (elementary, secondary, and combined), and census region (Northeast, Midwest, South, and West). The number of private school affiliation strata was reduced from 17 in 2003-04 to 11 in 2007-08. The current affiliation strata include
Catholic – parochial; Catholic – diocesan; Catholic – private; Baptist; Jewish; Lutheran; Seventh-Day Adventist; Other religious; Nonsectarian – regular; Nonsectarian – special emphasis; and Nonsectarian – special education.
Within each stratum, private schools in the list frame were systematically selected using a PPS algorithm. The measure of size used was the square root of the number of full-time- equivalent teachers. Any school with a measure of size larger than the sampling interval was excluded from the probability sampling process and included in the sample with certainty. About 2,940 private schools were sampled, 2,760 from the list frame and 180 from the 2005-06 PSS area frame.
School districts. Since the SASS sample design calls for schools to be selected first, the school district sample consists of the districts that were associated with the schools in the public school sample. This provides the linkage between the district and the school. However, in Delaware, Florida, Maryland, Nevada, and West Virginia, a different sampling method was used because an earlier simulation study revealed that in these states standard errors were high relative to the sampling rate. To improve the reliability of SASS school district estimates, all districts in these states were included in the sample. Placing all districts in each of these five states in the sample reduced the overall state standard error to zero, if all districts responded. About 5,250 public school districts were pulled into the sample by being associated with sampled public schools.
Teachers. Teachers are defined as staff who teach regularly scheduled classes to students in any of grades K-12. Teacher rosters (i.e., Teacher Listing Forms) were collected from sampled schools, primarily by mail, and compiled at the Census Bureau. This compilation was done on an ongoing basis throughout the roster collection period. Along with the names of teachers, sampled schools were asked to provide information about each teacher’s teaching experience (1-3 years, 4-19 years, and 20 or more years), teaching status (full- or part-time), and subject matter taught (special education, general