The analysis in this report is based on telephone interviews conducted from Sept. 15 to Oct. 13, 2015, among a nationally representative sample of 1,807 parents, 18 years of age or older, with children under 18, living in all 50 U.S. states and the District of Columbia (635 respondents were interviewed on a landline telephone and 1,172 were interviewed on a cell phone, including 697 who had no landline telephone). The survey was conducted by interviewers at Princeton Data Source under the direction of Princeton Survey Research Associates International.
A combination of landline and cell phone random digit dial (RDD) samples was used; both samples were provided by Survey Sampling International. Interviews were conducted in English and Spanish. Respondents in the landline sample were selected by randomly asking for the youngest adult male or female who was home at the time. Interviews in the cell sample were conducted with the person who answered the phone, if that person was an adult 18 years of age or older. To supplement the fresh RDD sample, interviews were completed among a sample of parents who recently participated in the PSRAI Weekly Omnibus survey and a recent Pew Research Center political survey. Approximately half of respondents were obtained from the RDD sample and half from the callback sample.
For the RDD sample, the combined landline and cell phone sample are weighted using an iterative technique that matches gender, age, education, race, Hispanic origin and nativity, and region to parameters of parents from the 2013 Census Bureau’s American Community Survey and population density to parameters from the 2010 Decennial Census. The sample also is weighted to match current patterns of telephone status (landline only, cell phone only, or both landline and cell phone), based on extrapolations from the 2014 National Health Interview Survey. The weighting procedure also accounts for the fact that respondents with both landline and cell phones have a greater probability of being included in the combined sample and adjusts for household size among respondents with a landline phone.
For the callback sample, the final weight used in the original survey was applied as the first-stage weight. The second stage of weighting balances sample demographics to population parameters of parents as described above. The population density and phone use parameters were derived from an analysis of all Pew political survey data collected in 2015. The margins of error reported and statistical tests of significance are adjusted to account for the survey’s design effect, a measure of how much efficiency is lost from the weighting procedures.
For detailed information about our survey methodology, see https://www.pewresearch.org/methodology/u-s-survey-research/
The following table shows the unweighted sample sizes and the error attributable to sampling that would be expected at the 95% level of confidence for different groups in the survey:
Sample sizes and sampling errors for other subgroups are available upon request.
In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.
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© Pew Research Center, 2015