The News Interest Index is a weekly survey conducted by the Pew Research Center for the People & the Press aimed at gauging the public’s interest in and reaction to major news events. This project has been undertaken in conjunction with the Project for Excellence in Journalism’s News Coverage Index, an ongoing content analysis of the news. The News Coverage Index catalogues the news from top news organizations across five major sectors of the media: newspapers, network television, cable television, radio and the internet. Each week (from Monday through Sunday) PEJ compiles this data to identify the top stories for the week. (For more information about the Project for Excellence in Journalism’s News Coverage Index, go to www.pewresearch.org/journalism.) The News Interest Index survey collects data from Thursday through Sunday to gauge public interest in the most covered stories of the week.
Results for this survey are based on telephone interviews conducted July 21-24, 2011, among a national sample of 999 adults 18 years of age or older living in the continental United States (602 respondents were interviewed on a landline telephone, and 397 were interviewed on a cell phone, including 169 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. 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.
The combined landline and cell phone sample are weighted using an iterative technique that matches gender, age, education, race, Hispanic origin, region, and population density to parameters from the March 2010 Census Bureau’s Current Population Survey. The sample is also weighted to match current patterns of telephone status 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.