About this survey
This report is based on the findings of several surveys of Americans about their use of the Internet. First, they are based on data from telephone interviews conducted by Princeton Survey Research Associates between September 5-27, 2001 (we made no calls on September 11), among a sample of 815 Internet users, 18 and older, who have ever gone online to look for information from a local, state, or federal government Web site. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects 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.
Interviews for this survey were completed from a pre-screened sample of Internet users who in past surveys identified themselves as government Web site users. Once the household was reached, interviewers asked to speak with the individual who had recently completed a telephone survey. Once the targeted person was on the phone, they were asked a few screening questions to make sure that they had ever gone online to use government Web sites.
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. The final response rate for this survey is 51%.
Second, the figures about the overall size of the online population of those who use government Web sites are drawn from the January 2002 daily tracking survey on Americans’ use of the Internet. The results in this report are based on data from telephone interviews conducted by Princeton Survey Research Associates between January 3 and January 31, 2002, among a sample of 2,391 adults, 18 and older – 1,451 of them are Internet users. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling is plus or minus 2 percentage points. For results based Internet users, the margin of sampling error is plus or minus 3 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.
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 likely to vary also on questions of substantive interest. In order to compensate for these known biases, the sample data are weighted in analysis. The demographic weighting parameters are derived from a special analysis of the most recently available Census Bureau’s Current Population Survey (March 2000). This analysis produces 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.
