acoolone's Blog

The term Bradley effect or (less commonly)[1] the Wilder effect refers to an explanation advanced as the possible cause of an alleged phenomenon which has led to inaccurate voter opinion polls in some American political campaigns between a white candidate and a non-white candidate.[2][3][4] Specifically, there were instances in which such elections saw the non-white candidate significantly underperform with respect to the results predicted by pre-election polls.

Researchers who studied the issue theorized that some white voters gave inaccurate polling responses because of a fear that by stating their true preference, they might appear to others to be racially prejudiced. This theory suggested that statistically significant numbers of white voters tell pollsters in advance of an election that they are either undecided, or likely to vote for the non-white candidate, but that those voters exhibit a different behavior when actually casting their ballots. White voters who said that they were undecided break in statistically large numbers toward the white candidate, and many of the white voters who said that they were likely to vote for the non-white candidate ultimately cast their ballot for the white candidate.

The reluctance to give accurate polling answers has sometimes extended to post-election exit polls as well. Some research suggested that the race of the pollster conducting the interview factored into voters' concerns. But some pollsters expressed doubts altogether that deliberately false answers from white voters being polled has been the cause of the polling errors in question. At least one prominent researcher has suggested that with regard to pre-election polls, the discrepancy can be traced in part by the polls' failure to account for general conservative political leanings among late-deciding voters.