Technical Notes

The sample of elementary and secondary schools for the FRSS survey on advanced telecommunications was selected from the 1993-94 NCES Common Core of Data (CCD) Public School Universe File. Over 84,000 public schools are contained in the CCD public school universe file. For this survey, elementary and secondary schools were selected. Special education, vocational education, and alternative schools were excluded from the survey along with schools that did not have at least first grade and those outside the 50 states and the District of Columbia. A stratified sample of 1,000 schools was selected from the public school frame. To select the sample, the frame of schools was stratified by instructional level (elementary, secondary) and by geographic region (Northeast, Southeast, Central, and West). Within these primary strata, schools were also sorted by metropolitan status (city, urban fringe, town, rural), size of enrollment (less than 300, 300-499, 500-999, 1,000-1,499, 1,500 or more), and percent minority enrollment (less than 5 percent, 5-19.9 percent, 20-49.9 percent, 50 percent or more). The allocation of the sample to the major strata was made in a manner that was expected to be reasonably efficient for national estimates, as well as for estimates for major subclasses.

In September 1996, questionnaires were mailed to the principals in the 1,000 sampled schools. The principal was asked to forward the questionnaire to the computer or technology coordinator or to whomever was most knowledgeable about the availability and use of advanced telecommunications at the school. Telephone followup of nonrespondents was initiated in late October, and data collection was completed in November. Five schools were found to be closed, and a total of 911 schools completed the survey. Thus, the final response rate was 92 percent (911 of 995 eligible schools).

The survey responses were weighted to produce national estimates. The weights were designed to adjust for the variable probabilities of selection and differential nonresponse. The findings in this report are estimates based on the sample selected and, consequently, are subject to sampling variability. The standard error is a measure of the variability of estimates due to sampling. It indicates the variability of a sample estimate that would be obtained from all possible samples of a given design and size. Standard errors are used as a measure of the precision expected from a particular sample. If all possible samples were surveyed under similar conditions, intervals of 1.96 standard errors below to 1.96 standard errors above a particular statistic would include the true population parameter being estimated in about 95 percent of the samples. This is a 95 percent confidence interval. For example, the estimated percentage of public schools with Internet access is 65 percent, and the estimated standard error is 1.8 percent. The 95 percent confidence interval for the statistic extends from 65 -(1.8 x 1.96) to 65 + (1.8 x 1.96), or from 61 to 69 percent. Estimates of standard errors for this report were computed using a technique known as the jackknife replication method. Standard errors for all of the estimates are presented in the tables. All specific statements of comparison made in this report have been tested for statistical significance using chi-square tests and t-tests adjusted for multiple comparisons using the Bonferroni adjustment and are significant at the 95 percent confidence level or better.

The survey estimates are also subject to nonsampling errors that can arise because of nonobservation (nonresponse or noncoverage) errors, errors of reporting, and errors made in collection of the data. These errors can sometimes bias the data. Nonsampling errors may include such problems as the differences in the respondents' interpretation of the meaning of the questions; memory effects; misrecording of responses; incorrect editing, coding, and data entry; differences related to the particular time the survey was conducted; or errors in data preparation. While general sampling theory can be used in part to determine how to estimate the sampling variability of a statistic, nonsampling errors are not easy to measure and, for measurement purposes, usually require that an experiment be conducted as part of the data collection procedures or that data external to the study be used. To minimize the potential for nonsampling errors, the questionnaire was pretested with public school technology coordinators and other knowledgeable respondents like those who completed the survey. During the design of the survey and the survey pretest, an effort was made to check for consistency of interpretation of questions and to eliminate ambiguous items. The questionnaire and instructions were extensively reviewed by the National Center for Education Statistics. Manual and machine editing of the questionnaire responses were conducted to check the data for accuracy and consistency. Cases with missing or inconsistent items were recontacted by telephone to resolve problems. Data were keyed with 100 percent verification.

The survey was performed under contract with Westat, Inc., using the NCES Fast Response Survey System (FRSS). Westat's Project Director was Elizabeth Farris, and the Survey Manager was Sheila Heaviside. Judi Carpenter, Shelley Burns, and Edith McArthur were the NCES Project Officers. The data were requested by Linda Roberts, U. S. Department of Education. This report was reviewed by the following individuals:

Outside NCES

• Oona Cheung, Council of Chief State School Officers


• Douglas A. Levin, Pelavin Research Institute/ American Institutes for Research


• David Osher, Pelavin Research Institute/ American Institutes for Research

Inside NCES

• Michael P. Cohen, Statistical Standards and Services Group


• Michael P. Cohen, Statistical Standards and Services Group


• Mary J. Frase, Data Development and Longitudinal Studies Group


• Gerald S. Malitz, Surveys and Cooperative Systems Group


• William H. Freund, Surveys and Cooperative Systems Group


• Kerry L. Gruber, Surveys and Cooperative Systems Group

For a copy of the questionnaire, Advanced Telecommunications in U. S. Public Schools, Fall 1996, or for more information about the Fast Response Survey System, contact Shelley Burns, Data Development and Longitudinal Studies Group, National Center for Education Statistics, Office of Educational Research and Improvement at http://nces.ed.gov.

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