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February 7, 2008

Super Tuesday results indicate race card may be a joker in primaries

The Bradley effect may be alive and multiplying after Super Tuesday.

Sifting through overnight results, UW researchers have found that race still plays a role in American politics and it showed up Tuesday in surprising ways in the tallies from four states holding Democratic primary elections. Early analysis of primary counts and polling data from the final week of the campaign indicated that pre-election polls exaggerated support for Sen. Barack Obama in two states with relatively low black populations — California and Massachusetts. But he benefited from a newly discovered “reverse” Bradley effect in Alabama and Georgia where blacks make up a larger bloc of voters.

The Bradley effect was first noticed by researchers in 1982 when black Los Angeles Mayor Tom Bradley had a solid lead in the pre-election gubernatorial polls, but lost a close election in California to his Republican opponent. Results from that and other races involving black candidates indicated that polling tended to overstate support for black candidates compared to their actual vote percentages.

Last December, Bethany Albertson, a UW assistant political science professor, and Anthony Greenwald, a UW psychology professor, analyzed data from an online test that measures unconscious or automatic preferences and surmised that the Bradley effect could well repeat itself in 2008.

The UW researchers had good late-polling data from 11 Super Tuesday states, as well as earlier data from New Hampshire and South Carolina. New Hampshire was another state that showed the Bradley effect, while South Carolina showed the reverse Bradley effect.

Greenwald said actual results of the Democratic primaries in California, Massachusetts, New Hampshire, South Carolina, Georgia and Alabama compared against late polling numbers all substantially exceeded the polls’ expected margin of error, being off between 8 and 18 percent. By contrast, they found Republican vote totals and poll numbers were only substantially off in Massachusetts where Mitt Romney’s winning margin was less than predicted.

The UW researchers plan to further investigate the Bradley and reverse Bradley effects as the 2008 election season plays out.

A graph illustrating how the Bradley and reverse Bradley effects have played out in 2008 primaries is available at: http://faculty.washington.edu/agg/Bradley_&_Reverse_Bradley.6Feb08.pdf