The reported early voting numbers, however, show that virtually every single Ohio poll overestimated the amount of early votes cast. If early voting is calculated at 1,787,346, in order for total voter turnout to rival 2004 numbers, early voting cannot occupy more than 32% of the total votes cast — and even in that scenario, that high of a percentage means that total voter turnout will be lower than it was in 2008. In order for turnout to match 2008 levels, early voting can only account for 31% of total votes cast. The next important piece of data is what the polls consistently report: Obama leads by huge margins among early voters but trails Romney among those who say they will vote on election day. This inverse in voting segments is why the proportion of early votes in the total votes — and that virtually every poll overestimated this proportion — is so tantamount. In most polls (which usually only have Obama leading by a small margin, although some give him a more comfortable ~+5%), lowering the percentage of early votes in the polling sample means lowering Obama’s lead drastically. And when Obama’s lead is only one or two percentage points, that can mean handing the election to Mitt Romney.
To break it down: In 2008 early voting in counties that Obama won were 67% of the total, with 33% of early votes coming from counties that voted for McCain. The same ratio in 2012? 64%/36%. BUT! Kerry/Obama counties showed a 10% decrease; Bush/McCain counties showed a 14% increase… and Bush/Obama (which is to say, counties that went for Bush in ’04 and Obama in ’08) counties showed a .6% increase. We know that absentee ballot requests across the board trended more Republican, so it seems fair to me that we can legitimately at least speculate that Bush/Obama counties are reverting back to the GOP… which means that the blue/red county ratio is much more likely to be closer to 53%/47%. If true, that is very bad news for Obama, because it means that he cannot hope to rack up the same early voting lead that he had in 2008.
I am amazed that they didn't figure this out sooner. LS, Ravi, and others have been tracking this for a month.