Each year, the Gallup Poll conducts the Public Attitudes Toward the Public Schools Survey, funded by the Phi Delta Kappa Educational Foundation. The survey includes interviews with adults representing the civilian noninstitutional population, age 18 and older.
Gallup uses an unclustered, directory-assisted, random-digit-dial telephone sample, based on a proportionate stratified sampling design. In 2000, the final sample was weighted so that the distribution corresponded with the U.S. Census Bureau's Current Population Survey (CPS) estimates for the adult population living in households with telephones in the continental United States. The sample used in the 39th (2007) annual survey was made up of a total of 1,005 adults age 18 and older. Field work for the survey was conducted between June 12 and June 29, 2007.
The survey is a sample survey and is subject to sampling error. The size of the error depends largely on the number of respondents providing data. Appendix table A-4 shows the approximate sampling errors associated with different percentages and sample sizes for the survey. Appendix table A-5 provides approximate sampling errors for comparisons of two sample percentages.
For example, an estimated percentage of about 10 percent based on the responses of 1,000 sample members maintains an approximate sampling error of 2 percent at the 95 percent confidence level. The sampling error for the difference in two percentages (50 percent versus 41 percent) based on two samples of 750 members and 400 members, respectively, is about 8 percent at the 95 percent confidence level.
Further information on the Public Attitudes Toward the Public Schools Survey may be obtained from
Delaine McCullough
Phi Delta Kappa
P.O. Box 789
Bloomington, IN 47402-0789
dmccullough@pdkintl.org
http://www.pdkintl.org/
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