High Quality Content by WIKIPEDIA articles! The Bradley effect, less commonly called the Wilder effect, is a theory proposed to explain observed discrepancies between voter opinion polls and election outcomes in some United States government elections where a white candidate and a non-white candidate run against each other. The theory proposes that some voters will tell pollsters they are undecided or likely to vote for a black candidate, while on election day they vote for the white candidate. It was named after Los Angeles Mayor Tom Bradley, an African-American who lost the 1982 California governor`s race despite being ahead in voter polls going into the elections.