Virtually every Ohio poll this cycle was weighted on the basis that early voting would occupy a massive chunk of the total Ohio vote. Rasmussen's final poll ceded 40% of the total vote to early voters (EVs). PPP gave EV's a more reasonable 35%. The Columbus Dispatch calculated early voting to take up an astounding 47% of the total Ohio vote. Almost every other Ohio poll seems to have weighted early voting between 35% and 45% of the total vote.
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.
Our forecast is based largely on the reported margins between Romney and Obama among early voters and election day voters as reported by the Columbus Dispatch, Rasmussen, and other polls (all polling data considered is represented in the graphic below). The Columbus Dispatch gives Obama +15% among early voters; Rasmussen gives him a much wider 23%. Other polls for Ohio EVs: CNN/Opinion Research, Obama +28; Gravis Marketing, Obama +13; PPP, Obama +21. For our forecast we assumed a more conservative Obama +18 among EVs, averaging Rasmussen and the Columbus Dispatch.
Based on these assumptions — which in turn are based on a combination of polling data and the state's actual reported early vote — if early voting accounts for 32% of the vote (a very conservative number which would place total voter turnout slightly below that of 2004), Romney wins by a whopping 50.9% to Obama's 47.8%. The higher voter turnout is — and therefore the lower the percentage of early votes in total votes — the higher Romney's margin becomes.
In this scenario, even if we assume our model's margins between Obama and Romney among early voters and election day voters are somehow skewed in Romney's favor, Romney still has padding that those margins could be reduced and he still wins. If early voting is only 31% of the total vote — putting Ohio's total vote at just above 2008 levels — Romney has incredibly more wiggle room.
The lower-than-anticipated turnout among early voters suggests the Obama campaign's lead in Ohio was largely hot air. And this does not even seriously consider the county-by-county early voting results, which appear to be even more damaging to Obama.
Tuesday, November 6, 2012
Early Voting Results Suggest Trouble for Obama in Ohio
It looks like all the polls overestimated the early vote, which always broke heavily for Obama: