About the Survey
The analysis in this report
is based on telephone interviews conducted Nov. 9-14, 2011, among a national
sample of 2,001 adults, 18 years of age or older, living in all 50 U.S. states
and the District of Columbia (1,200 respondents were interviewed on a landline
telephone, and 801 were interviewed on a cell phone, including 397 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
samples were 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 is now at home. 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. For detailed information about our survey methodology, see http://people-press.org/methodology/
The combined landline and
cell phone sample are weighted using an iterative technique that matches
gender, age, education, race, Hispanic origin and nativity, region, and
population density to parameters from the March 2010 Census Bureau's Current
Population Survey. The sample also is weighted to match current patterns of
telephone status and relative usage of landline and cell phones (for those with
both), based on extrapolations from the 2010 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 within the landline sample.
Sampling errors and statistical tests of significance take into account the
effect of weighting. The following table shows the 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.
To view the topline, download the full report.