PDF & Related InfoThe sampling frame for the FRSS Survey on Advanced Telecommunications in U.S. Private Schools: 1998-99 was constructed from the 1997-98 NCES Private School Survey (PSS) Universe File, the most recent file available at the time the sample was selected. The PSS Universe File has two components: list frame and area sample. The complete file represents 27,402 schools, including 8,182 Catholic schools, 13,195 schools with religious affiliations other than Catholic, and 6,025 nonsectarian schools. By level, the file represents 16,623 elementary schools, 2,487 secondary schools, and 8,292 combined elementary/secondary grades schools.
A private school was defined as a school not in the public system that provides instruction for any of grades 1 - 12 (or comparable ungraded levels) where the instruction was not provided in a private home. All regular private elementary, secondary, and combined schools in the 50 states and the District of Columbia were included in the sampling frame. Special education, vocational, early childhood/day care, and alternative schools, and schools having a high grade of prekindergarten, transitional kindergarten, kindergarten, or ungraded were excluded from the frame prior to sampling. Thus, the final sampling frame included 24,128 eligible private schools enrolling over 5.2 million students (table A-1).
The private school sampling frame was sorted by type of locale (city, urban fringe, town, and rural). Within the primary strata, schools were also sorted by level (elementary, secondary, combined), affiliation (Catholic, other religious, nonsectarian), and school size (under 100, 100- 299, 300-499, 500-999, 1,000 or more). Schools were then selected from each primary stratum with probabilities proportional to wi, where wi is the weight reflecting the school's probability of inclusion in the area sample (for schools in the PSS list frame, wi = 1). The within-stratum sampling rates were designed to yield selfweighted samples of schools in each primary stratum. Although the samples were selfweighted within primary strata, the overall probabilities varied by school size, with larger schools having higher probabilities of selection than smaller ones. Such a design is reasonably efficient for estimating the proportion or number of schools with specified characteristics (e.g., the proportion of private schools with access to the Internet), as well as statistics that are correlated with enrollment (e.g., the percent of private school students or teachers who have access to the Internet).
In February 1999, survey instruments (see Appendix C) were mailed the heads of 999 private schools, who were asked to forward the questionnaire to the person most knowledgeable about the availability and use of advanced telecommunications at the school. The accompanying instructions requested that the school complete the self-administered questionnaire and return it by mail using the postage-paid envelope or by fax using a toll-free number. Telephone followup was conducted with schools that did not complete the survey. Of the 999 schools in the sample, 16 were found to be out of the scope of the survey, for a total of 983 eligible schools. The unweighted response rate was 86 percent. The weighted response rate was 84 percent.
Survey responses were weighted to produce national estimates. For estimation purposes, sampling weights were attached to each school data record. The sampling weights reflect each school's overall probability of selection and include upward adjustments to compensate for differential nonresponse. The findings in this report are estimates based on the sample selected and, consequently, are subject to sampling variability.
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 and place 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 difficult 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 survey was pretested with private school technology directors and coordinators and other individuals knowledgeable about the availability and use of advanced telecommunications. During the survey design process and the survey pretest, an effort was made to check for consistency of interpretation of questions and to eliminate ambiguous terms as a result. The questionnaire and instructions were extensively reviewed NCES. 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 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 known as a 95 percent confidence interval. For example, the estimated percentage of private schools with Internet access is 67 percent, and the standard error is 2.1 percent. The 95 confidence interval for the statistic extends from 67 - (2.1 x 1.96) to 67 + (2.1 x 1.96), or from 63 percent to 71 percent.
To properly reflect the complex features of the sample design, standard errors of the surveybased estimates were calculated using jackknife replication. As with any replication method, jackknife replication involves constructing a number of subsamples (replicates) from the full sample and computing the statistic of interest for each replicate. The mean square error of the replicate estimates around the full sample estimate provides an estimate of the variances of the statistics. To construct the replications, 50 stratified subsamples of the full sample were created and then dropped one at a time to define 50 jackknife replicates. A computer program, WesVarPC, was used to calculate the estimates of standard errors. WesVarPC is a stand-alone Windows application that computes sampling error for a wide variety of statistics (totals, percents, ratios, log-end ratios, general functions of estimates in tables, linear regression parameters, and logistic regression parameters).
Bonferroni adjustments were made to control for multiple comparisons where appropriate. For example, for an "experimentwise" comparison involving g pairwise comparisons, each difference was tested at the 0.05/g significance level to control for the fact that g differences were simultaneously tested.
Advanced telecommunications - refers to modes of communication used to transmit information from one place to another including broadcast and interactive television, networked computers, etc.
School affiliation - Schools were classified according to their affiliation as identified on the Private School Survey (PSS) Universe File.
Catholic
- schools affiliated with the Catholic Church.Other religious
- schools affiliated with religions or with a religious orientation other than Catholic.
Nonsectarian
- schools that are not affiliated with a church or a religious orientation.
Elementary
- a school that had grade 6 or lower, or "ungraded" and no grade higher than 8th. It would include schools comprised of students in grades 1 through 6, students in grades 7 and 8 when the remainder of the students in the school are in the lower grades or are ungraded, and students in ungraded classes in schools with no grade higher than the 8th grade.Secondary
- a school that had no grade lower than the 7th, or "ungraded" and had grade 7 or higher. This category includes schools composed of students in grades 9 through 12, students in grades 7 and 8 when the remainder of the students in the school are in grades above 8th or are ungraded, and students in ungraded classes in schools with no grade lower than 7th.Combined
- a school that has grades higher than the 8th and lower than the 7th. It includes schools composed of students in any grade in schools that range below grade 7 and above grade 8, or of students that are all in ungraded classes.
Less than 150
- considered schools with relatively small enrollments for analytical purposes.
150-299
- considered medium-sized schools for analytical purposes.
300 or more
- considered large schools for analytical purposes.
City
- a central city of a Standard Metropolitan Statistical Area (SMSA).Urban fringe
- a place within an SMSA of a large or mid-size central city and defined as urban by the U.S. Bureau of the Census.Town
- a place not within an SMSA, but with a population greater than or equal to 2,500, and defined as urban by the U.S. Bureau of the Census.Rural
- a place with a population less than 2,500 and defined as rural by the U.S. Bureau of the Census.
Less than 5 percent
- less than 5 percent of the students enrolled in the school were American Indian or Alaskan Native; Asian or Pacific Islander; Hispanic, regardless of race (Mexican, Puerto Rican, Cuban, Central or South American, or other Spanish culture or origin); or black (not of Hispanic origin).5 to 19 percent
- between 5 and 19 percent of the students enrolled in the school were members of a racial/ethnic minority.
20 to 49 percent
- between 20 and 49 percent of the students enrolled in the school were members of a racial/ethnic minority.
50 percent or more
- between 50 and 100 percent of the students enrolled in the school were members of a racial/ethnic minority.
The survey was performed under contract with Westat, using the NCES Fast Response Survey System (FRSS). Westat's Project Officer was Elizabeth Farris, the survey manager was Rebecca Skinner, and the main author was Basmat Parsad. Westat's operations manager was Debbie Alexander and the research assistant for the project was Anne Cattagni. Shelley Burns was the NCES Project Officer. The data were requested by Jack Klenk of the Office of Non-Public Education, U.S. Department of Education.
This report was reviewed by the following individuals:
For a copy of the questionnaire, Advanced Telecommunications in U.S. Private Schools, 1998-99, or for more information about the Fast Response Survey System, contact Shelley Burns, Early Childhood, International and Crosscutting Studies Division, National Center for Education Statistics, Office of Educational Resarch and Improvement, U.S. Department of Education, 1990 K Street, NW, Washington, DC 20006, e-mail: Shelley_Burns@ed.gov, telephone (202) 502-7348. This report and other NCES reports are available on the NCES Web site at http://nces.ed.gov.
