Hello all, I know it’s been forever and a day since we’ve been around. Time to get back into the numbers.John McCain is pulling close to Barack Obama in projected electoral votes, according to a relatively new political web site called FiveThirtyEight.com (538=number of electoral votes). The site in run by Nate Silver, who is a sabermatician–concerned more typically about baseball statistics than election polling. According to Silver, his method differs from others in several ways:
Firstly, we assign each poll a weighting based on that pollster’s historical track record, the poll’s sample size, and the recentness of the poll. More reliable polls are weighted more heavily in our averages.Secondly, we include a regression estimate based on the demographics in each state among our ‘polls’, which helps to account for outlier polls and to keep the polling in its proper context.Thirdly, we use an inferential process to compute a rolling trendline that allows us to adjust results in states that have not been polled recently and make them ‘current’.Fourthly, we simulate the election 10,000 times for each site update in order to provide a probabilistic assessment of electoral outcomes based on a historical analysis of polling data since 1952. The simulation further accounts for the fact that similar states are likely to move together, e.g. future polling movement in states like Michigan and Ohio, or North and South Carolina, is likely to be in the same direction.
His method has Obama at 272.3 and McCain at 265.7, and Ohio is the swing state. His scenario simulations give Obama only a 17.9% chance of winning if he loses Ohio, whereas McCain is given a 0.42% chance–less than 1 out of 200–of winning the election if he loses Ohio. Pollster.com currently has Obama up 45.6% to 43.9% in Ohio.