The Pew Research Center’s 2013 report on its survey of American Jewry led to vigorous discussion, and much hand-wringing, in the Jewish community. Now Pew has released a similar report on the state of American Christianity, generating similar discussion among Christians. Tracing the history of polling about religion, Robert Wuthnow points to some of its problems:
Polling’s credibility depends on a narrow definition of science and an equally limited understanding of the errors to which its results are subject. Its legitimacy hinges mostly on predicting elections and making news. With few exceptions, polling about religion is an industry based on the use of the single method of asking questions in a survey, not on multiple methods or extensive knowledge about religion itself. Above all, it depends on a public that is willing to believe that polls are sufficiently valuable to spend the time it takes to answer questions when pollsters call. . . . . [And as] public confidence in polls has tanked, so has the public’s willingness to participate in polls. . . .
[I]f declining response rates leave unanswered questions, what we do know from polls—or think we know—needs to be regarded with much greater caution than is typically the case in journalistic coverage. . . . [J]udging from academic surveys that still have high response rates and ask good questions, the [widely-cited] polling estimate of 90- to 100-million weekly churchgoers is off by about 30 million. If political polling were off by that much, it would be scandalous.