Pew Research CenterJanuary 7, 2016

Appendix B: The choice of a turnout measure

There are two indicators of voter turnout available for the type of analysis in this report: (1) each respondent’s self-report in the post-election survey and (2) a voter file record of turnout. Among registered voters, 63% have a voter file record indicating that they voted in 2014 (“verified voters”) and 75% said they voted (“self-reported […]

Pew Research CenterJanuary 7, 2016

Appendix A: The Perry-Gallup measures

The items used in the so-called Perry-Gallup scale – originally developed in the 1950s and ’60s by election polling pioneer Paul Perry of Gallup and used in various combinations and with some alterations by the Pew Research Center, Gallup and other organizations in their pre-election polling (Perry 1960, 1979) – are widely employed by survey […]

Pew Research CenterJanuary 7, 2016

Methodology

The American Trends Panel surveys (ATP) The American Trends Panel (ATP), created by Pew Research Center, is a nationally representative panel of randomly selected U.S. adults living in households. Respondents who self-identify as internet users (representing 89% of U.S. adults) participate in the panel via monthly self-administered Web surveys, and those who do not use […]

Pew Research CenterJanuary 7, 2016

Acknowledgements

This report is a collaborative effort based on the input and analysis of the following individuals: Primary Researchers Scott Keeter, Senior Survey Advisor Ruth Igielnik, Research Associate Andrew Mercer, Research Methodologist Jocelyn Kiley, Associate Director, Research Collaborating Researchers Claudia Deane, Vice President, Research Michael Dimock, President Ken Goldstein, University of San Francisco Courtney Kennedy, Director […]

Pew Research CenterJanuary 7, 2016

4. Conclusion

The analysis presented here suggests that modeling the electorate is likely to continue to vex pollsters, especially if no official record of past voting is available as an input to the models. As if to affirm this somewhat pessimistic conclusion, polls have failed to accurately predict winning candidates in several recent elections, including the 2015 […]

Pew Research CenterJanuary 7, 2016

3. Comparing the results of different likely voter models

All told, we tested 16 different variations on four types of likely voter methods, producing estimates that range from a 2-point Democratic lead to a 7-point Republican advantage in the generic U.S. House vote. The benchmark for comparison is a 3-point Republican lead among verified voters (49% Republican, 46% Democratic) when they were interviewed prior […]

Pew Research CenterJanuary 7, 2016

2: Measuring the likelihood to vote

The survey literature has long shown that more respondents say they intend to vote than actually cast a ballot (e.g., Bernstein et al. 2001; Silver et al. 1986). In addition, some people say they do not expect to vote but actually do, perhaps because they are contacted by a campaign or a friend close to […]

Pew Research CenterJanuary 7, 2016

1. Polls and votes: The 2014 elections by the numbers

Our equivalent of a crystal ball – the voter file, combined with a post-election survey interview – provides us with a validated record of turnout for our survey respondents. Our post-election survey provides us with the respondents’ report of how they voted. This allows us to see how a Democratic advantage among registered voters in […]

MethodsJanuary 7, 2016

Can Likely Voter Models Be Improved?

High-profile polling failures in recent elections have drawn attention to the challenges in using surveys to predict outcomes. Our study examines various methods of determining who is a likely voter.

HispanicDecember 10, 2015

Supreme Court could reshape voting districts, with big impact on Hispanics

How the Supreme Court decides a redistricting case from Texas could affect Hispanic voting strength and House representation from coast to coast.