Accuser’s press conference cuts Herman Cain’s odds in half in prediction markets

Sharon Bialek, the fourth woman to allege that Herman Cain sexually harassed her--and the first to do so live on television--spoke to the news media on Monday. Bialek's press conference appears to have cut Herman Cain's chances of winning the Republican presidential nomination almost in half.

Just before it was announced that a woman and her attorney, Gloria Allred, would be holding a press conference Monday, the prediction markets gave Cain a 6.8 percent chance of becoming the Republican Party's presidential nominee. By the time the press conference ended, Cain's chances in the prediction markets had dropped to 3.8 percent.

I do not know how long it will take for public opinion polls to reflect Cain's weakened position in the presidential race, but the prediction markets have spoken: There is more than a 96 percent likelihood that Cain will fall in the public-opinion polls before Republicans cast their real votes in the 2012 primaries and caucuses.

Cain's likelihood of winning the Republican nomination was 8.5 percent just before the harassment allegations were first reported by Politico last week. When the allegations surfaced, Cain suffered a small drop in the prediction markets, but he leveled off quickly. Major news outlet reported that Cain was holding steady in the polls. The campaign itself bragged about its fundraising in the wake of the allegations.

Stay current by checking out the real-time likelihoods of each candidate winning the Republican presidential nomination.

David Rothschild is an economist at Yahoo! Research. He has a Ph.D. in applied economics from the Wharton School of Business at the University of Pennsylvania. He wrote his dissertation on creating aggregated forecasts from individual-level information. Follow him on Twitter @DavMicRot and email him at PredictionBlogger@Yahoo.com.