David Strömberg

WH 2008 Analysis, Nov. 3

Phone: +46 8 16 43 77
Fax: +46 8 16 14 43
E-mail: info@iies.su.se
Webmaster:
www@iies.su.se

Last updated,

 October 1, 2008

How the probabilities are estimated

Compared to the previous analysis on October 29. Obama's chances of winning have risen slightly, from 84 to 87 percent. This is partly due to less remaining uncertainty and partly due to Obama's improved standing in the polls.

 Obama has an 87 percent chance of winning the elections, receiving an average vote-share of 53 percent of the two-party vote share and an average 325 electoral votes. The risk that the president elect will not receive a majority of the popular votes is around 7 percent. It is more likely that Obama will be in this position (4 percent) than McCain (3 percent). Consequently, Obama benefits slightly from having the Electoral College system (this increases his chances of winning by 1 percent).  

The Bradley effect

I have estimated the Bradley effect based on 421 elections for House, Senator and Governor, 1998-2006, containing 26 black candidates. The effect is 2-3 percent of the two-party vote share. If there will be a Bradley effect of the same size as the average for the 22 House, Senate and Governor races 1998-2006 for which I have data. The statistics are the following.

The table below show the forecasted democratic vote shares (absent the Bradley effect), win percentages and the share of candidate visits that should go to each state, based on opinion polls available November 3.