Methodology
The report is based on the findings of a daily tracking survey on Americans’ use of the Internet. The results contained in this report are based on data from 11 months of telephone interviewing conducted by Princeton Survey research Associates between March 1, 2000 and December 22, 2000 as well as between February 1 and February 28, 2001. The March-December 2000 survey work generated a sample of 26,094 adults – those who are 18 and older. The 2000 surveys included 1,842 Hispanics and 904 Hispanics who use the Internet. The February 2001 survey generated a sample of 2,096 American adults, including 132 Hispanics, of whom 74 were Internet users.
For results based on the total sample from the 2000 interviews, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 1 percentage point. For results based on all Hispanics interviewed in 2000, the margin of sampling error is plus or minus 2 percentage points; for results based on Hispanic Internet users, the margin of sampling error is plus or minus 4 percentage points. In addition to sampling error, question wording, and practical difficulties in conducting telephone surveys may introduce some error or bias into the findings of opinion polls.
The sample for this survey is a random digit sample of telephone numbers selected from telephone exchanges in the continental United States. The random digit aspect of the sample is used to avoid “listing” bias and provides representation of both listed and unlisted numbers (including not-yet-listed numbers). The design of the sample achieves this representation by random generation of the last two digits of telephone numbers selected on the basis of their area code, telephone exchange, and bank number.
A new sample was released daily and was kept in the field for at least five days. This insures that the complete call procedures are followed for the entire sample. Additionally, the sample was released in replicates to insure that the telephone numbers called are distributed appropriately across regions of the country. At least 10 attempts were made to complete an interview at every household in the sample. The calls were staggered over times of day and days of the week to maximize the chances of making contact with a potential respondent. Interview refusals were re-contacted at least once in order to try again to complete an interview. All interviews completed on any given day were considered to be the final sample for that day.
Non-response in telephone interviews produces some known biases in survey-derived estimates because participation tends to vary for different subgroups of the population, and these subgroups are also likely to vary on questions of substantive interest. In order to compensate for these known biases, the sample data are weighed in analysis. The demographic weighting parameters are derived from a special analysis of the most recently available Census Bureau’s Current Population Survey (March 1999). This analysis produced population parameters for the demographic characteristics of adults age 18 or older, living in households that contain a telephone. These parameters are then compared with the sample characteristics to construct sample weights. The weights are derived using an iterative technique that simultaneously balances the distribution of all weighting parameters.
Throughout this report, the survey results are used to estimate the approximate number of Americans, in millions, who engage in Internet activities. These figures are derived from the Census Bureau’s estimates of the number of adults living in the telephone households in the continental United States. As with all survey results, these figures are estimates. Any given figure could be somewhat larger or smaller, given the margin of sampling error associated with the survey results used in deriving these figures.
About the Pew Internet & American Life Project
The Pew Internet & American Life Project is a non-profit initiative fully funded by The Pew Charitable Trusts. The Project creates original research that explores the impact of the Internet on children, families, communities, health care, schools, the work place, and civic/political life. The Pew Internet & American Life Project aims to be an authoritative source for timely information on the Internet’s growth and societal impact, through research that is scrupulously impartial. For more information, please visit our Web site: https://legacy.pewresearch.org/internet/.
