Some of these methods were developed because of the challenges associated with conducting telephone surveys. Although nearly all U.S. adults now have access to a telephone, survey researchers typically achieve relatively low response rates in telephone surveys of the U.S. public. For example, the Gallup Poll Social Series (GPSS) surveys achieved a 7% response rate, on average, in 2017, compared with 28% in 1997. Response rates are calculated according to standards put forth by the Council for American Survey Research Organizations (CASRO) and the American Association for Public Opinion Research (AAPOR) and represent the total number of completed interviews among all eligible households in the sample.
Gallup is not alone. Declining response rates have been reported throughout the survey research industry. The American Association for Public Opinion Research (AAPOR) released response rates from leading survey research firms in its 2015 report, The Future of U.S. General Population Telephone Surveys. The report detailed consistent declines from 2008 to 2015 across all participating organizations. During this period, landline response rates declined from an average of 15.7% to 9.3% and cellphone response rates declined from an average of 11.7% to 7.0%.
Cooperation rates -- the percentage of respondents who agree to complete the interview at the start of the survey -- have also consistently declined over time. In 1997, the average GPSS cooperation rate was 50%, meaning about half of all respondents who answered the phone agreed to proceed with the interview. In 2017, the average cooperation rate for this study was exactly half that -- 25%. Completion rates -- the percentage of respondents who complete the survey among those who started it -- have also declined, although less precipitously from an average of 92% in 1997 to an average of 84% in 2017.