Reply #4: For starters, from Ray Fair himself, a couple of mild concessions:

[swag]

"Ray Fair:

Given the current prediction of the equation that Bush will get over 57 percent of the two-party vote, does this mean that a Bush victory is a sure thing? The answer is no. First, the prediction is based on a particular set of economic forecasts (the current forecasts from my economic model), and if the economy does not do as well as this set says, the vote prediction for Bush will go down. Second, even if the equation is correctly specified, it makes on average an error of about 2.4 percentage points each election (called the "standard error"). Third, the equation may be misspecified. This is where the pitfalls come in.

possible pitfall is that the equation is misspecified because it does not have a job growth variable in it, only an output growth variable. Historically output growth and job growth are so highly correlated that very similar estimates are obtained using either. They are too highly correlated for one to be able to estimate separate effects. If in 2004 output growth is fairly good, but job growth is not, this would lead the equation to be off if job growth is in fact more important in voters' minds than output growth."