2012: A Close Race, With a High Degree of Uncertainty

2012: A Close Race, With a High Degree of Uncertainty

By Sean Trende - November 6, 2012

Though it's always tempting to draw historical analogies between elections, each contest is invariably unique. This year is no exception. We have an incumbent president -- who also happens to be the nation's first African-American to hold that office -- facing the electorate in challenging economic circumstances. He is trailing his opponent with independent voters and on many of the issues that voters say they care most about, yet on Election Day his approval rating is right up against the 50 percent mark and he maintains a slight edge in the polls.

As a political analyst, this election is also unique in that it’s the country’s first true “data-driven” election. I mean two things by that; first, that statistics-based political analysis has become a booming cottage industry over the last four years. We now have more “data junkies” providing often thought-provoking analysis than ever before.  In fact, as someone who began his writing career attempting to apply a more rigorous approach to political analysis, I can honestly say we're probably at the point where a course correction is necessary the other way. 

The second thing I mean about this being a “data driven” election is that, unlike the five previous elections I’ve covered closely, as we sit here on Election Day we still have multiple data points to evaluate.  Remember, data is the plural form of datum. Usually by this point in an election, we don’t have data; things have converged to form a single datum, which you don’t have to squint very hard to see.

For example, in 2008 some of the state polls were off (about which more later), but the errors canceled each other out, as we’d expect. But the big picture was clear.  Weighted by the number of votes cast in each state, the 2008 state polls projected that Obama would win the popular vote with 53.5 percent to McCain’s 46.4 percent. This was roughly the same projection as the national pollsters found, and indeed is roughly the same as the final total.

But this year, there is a divergence between what the state polls are seeing and what the national polls are seeing. Right now the RCP Average has Obama up 0.7 points. That’s probably a bit favorable to him: the median and mode for the distribution is a tie.

Compare this to what we see if we weight the various pollsters’ projections of each state’s vote by the number of votes cast in those states in 2008. Huffington Post/Pollster’s state projections collectively show Obama with a 2.4 percent lead, 538 shows him with a 2.1 percent lead, while Drew Linzer’s Votamatic projections say 2.7. RealClearPolitics shows a 1.8 percent lead for Obama. On average, the various state poll aggregation methods imply a 2.3 percent lead for the president.

As I noted last week, using this method negates the possibility that Romney is simply overperforming in the very red or very blue states. We have a reasonable amount of polling in very blue states such as California, New York, and Illinois; by building those data into our weighted averages, we would pick up on any such divergence.

Moreover, Obama presently leads by 2.8 points in the state most likely to give him electoral vote number 270 (Nevada, as his present lead in Ohio is statistically indistinguishable at 2.9 points). This represents a 2.1 point split between the state that would give him electoral vote 270 and the popular vote, and a 2.8 point split between that state and the median.

As I noted earlier, a split of more than a point between the margin in the state that gives electoral vote number 270 and the popular vote total is highly unlikely. A split of more than two points in a two-way race would be unprecedented. Going back 100 years, it has only happened twice: In the bizarre four-way race of 1948 and the three-way race of 1912 (even in that year, if you add together the two Republicans, the split is less than a point). My guess is you have to go back to 1876 to find a three-point split, and Republicans stole that election (technically, they stole it back after Democrats stole it first by suppressing the black vote in the South).

So we can be reasonably certain that the split we’re seeing between state and national polling is “real.” As a final check, we can go through the various methods described above, and create PVIs, or Partisan Voting Indexes, for each state in the various methodologies. In other words, the states in RealClearPolitics’ averages imply a 1.8-point lead for Obama. Right now, Obama’s lead in Ohio is 2.9 points. The difference in spreads is about 1.2 points, which means Obama runs about 0.6 points ahead of the national average there. This is quite a bit more than the spread we see between the Ohio average and the mean/medians for the national vote.

If you do that for all of the swing states, using the varying methodologies, you get the following results:

On the right, I’ve included a PVI for Rasmussen Reports’ results, based off of the average he was showing for Romney at the time the poll was taken (usually Romney up by two). This isn’t to show any particular favor to Rasmussen; he’s just a prolific pollster who has polls in both the RCP state and national averages. On the far right we see the Cook PVI for the state, and the standard deviation (a measure of how much variation we see in numbers) for the four major methods.

Each of the cumulative state poll estimates are seeing the same basic thing in terms of where each individual state lands. The states also match up roughly to the Cook PVI for the state, as does Rasmussen’s polling. The only difference in the “topline” numbers you see displayed on the site is how the states, taken as a whole, see the national environment shaping up.

Most importantly, all of the methods see the swing states falling within a point of the national vote margin. Again, this is just another piece of evidence that state pollsters and national pollsters are seeing two different things. And there’s no ready way to reconcile the two.

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Sean Trende is senior elections analyst for RealClearPolitics. He is a co-author of the 2014 Almanac of American Politics and author of The Lost Majority. He can be reached at Follow him on Twitter @SeanTrende.

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