The “Bradley effect” Is Alive and Well For SSM Polling

New research from the University of Maine’s Richard Powell:

Prior public opinion research has identified a wide range of circumstances in which polling results may be tainted by social desirability bias. In races pitting a Black candidate against White opponents, this has often been referred to as the “Bradley effect” (aka “Wilder effect” or “Dinkins effect”), by which survey respondents overstate their preference for Black candidates running against White opponents. This study examines the accuracy of polling on same-sex marriage ballot measures relative to polling on other statewide ballot issues in all states voting on the issue from 1998 to 2012, controlling for a range of theoretically relevant contextual factors. There has been a great deal of speculation, though little empirical evidence, that polling systematically understates opposition to same-sex marriage. Consistent with social desirability bias, this study finds that opposition to same-sex marriage is about 5% to 7% greater on election day than in preelection polls.

The next frontier for marriage equality will be getting people to say what they think and do what they say.


2 Responses to The “Bradley effect” Is Alive and Well For SSM Polling

  1. Clay Shirky says:

    On the contrary, the next frontier is getting people who oppose it to lie to their friends and family in addition to lying to pollsters.

    The lesson of the Dinkins Effect (which I lived through as a campaigner for Dinkins) is that over time, political correctness works, because when a prejudice becomes so socially inappropriate that people can no longer broadcast that prejudice without fear of consequence, it is weakened.

    What we want is a further increase in the radius of hypocrisy, until the time that people who are generally on the fence about the issue can’t identify any casual friends or co-workers who are overtly prejudiced.

    • Eric Horowitz says:

      That’s a good point, although I suppose one could argue that stating a true and unpopular position makes you more likely to receive a scolding from a social connection, and that could speed up the rate at which your own position shifts (although that says nothing about how your position influences others.)

      I wonder if there’s a dynamic where once a position receives majority support, any public discourse will reflect that majority, thereby generating social pressure that increases it. When the majority is extremely large (say, >80%-90%), it’s possible that this dynamic could reverse itself as public discussion gives the little-known minority a chance to air their points and provide some social cover for people to abandon the majority. Perhaps something like this is happening with recent public opinion on drones.

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