Individuals find polls that favor their candidates more credible

As the 2020 U.S. presidential election approaches, the public will be barraged with opinion polls seeking to assess attitudes toward the candidates and on leading campaign issues. Of concern to researchers is how partisan biases may influence the perception of these polls and, subsequently, voting behavior. A recent study by researchers at the Annenberg Public Policy Center (APPC) and the University of Michigan found that individuals are likely to find polls more credible when their preferred candidate is leading in them.

The researchers say these biases have potentially deleterious outcomes for democracy. "Biased perceptions of polls can affect election turnout and voting preferences," says APPC postdoctoral fellow Ozan Kuru, lead author of the study, which was published in the International Journal of Public Opinion Research.

The study suggests that there are potential benefits of emphasizing polls' methodological quality—for example, whether a poll's sample is nationally representative—to help reduce partisan biases in poll evaluations.

"If people focus on these objective aspects of polls," Kuru says, "they may be less likely to immediately dismiss results that they find unfavorable. This framework could also be applied to the communication of other metrics of public opinion in news reports—such as polling averages, forecasting models, analysis of social media content, and election prediction markets—as well as official public statistics such as unemployment rates, census data, and election outcomes."