Nate Silver of FiveThirtyEight is a journalist, not a political scientist. However, he knows the “tools of the trade” that political scientists commonly use to understand election statistics. He’s also much more familiar with political science research than the average journalist. I read his column regularly and agree with his analysis and conclusions more often than not.
His latest article is published today in the New York Times. He describes a series of 2012 election forecasts that he has produced based on three key factors: economic growth, Obama’s approval rating, and the ideology of the GOP candidate. His bottom line conclusion is that if the Republicans nominate Mitt Romney (which is looking increasingly likely), and if the economy grows as expected (low-to-moderate levels) over the next year, then President Obama has about a 50/50 shot of winning a second term. The president’s prospects would decrease if GDP growth rate in 2012 is less than 2% and would become very positive if GDP growth in 2012 is more than 4%. Interestingly, this coincides almost exactly with the forecast of the “bread and peace” model that I described in a previous post. Also, Obama’s reelection prospects are at exactly 50% in today’s Intrade betting markets.
My only qualm about his forecasting model is that I think he overstates the effect of candidate ideology on the outcome of the election. Nate is to be commended for admitting out front that the ideology of the GOP candidate is less important than the economy of president’s approval rating, but this variable is rarely included in other election forecasting models that political scientists use for one simple reason: most (but certainly not all) Republicans (and Independents who lean Republican) will vote for the Republican candidate regardless of whether he or she is ideologically moderate or extreme. (Think McCain 2008: about 90% of Republicans and Indy-Republicans voted for him and about 90% of Democrats and Indy-Democrats voted against him despite his moderate political ideology.).
Other than that, I think that Nate is much more “on the mark” than most other journalists. It’s also worth noting that this model does not include things like the effect of debates, turnout efforts, advertising, etc. But this is a strength of the model, in that those things tend to matter only at the margins.
Full article available here: http://www.nytimes.com/2011/11/06/magazine/nate-silver-handicaps-2012-election.html?_r=1&pagewanted=print
An interactive calculator where you can play with the three variables in the model is available here: http://www.nytimes.com/interactive/2011/11/03/magazine/538-gdp-election-calculator.html