It was fun to learn of David Brooks’s addiction to polling data. He spends countless hours on them, looking at aggregators, examining individual polls, and sniffing poll internals. From all of this, what has he learned?
- Today, President Obama would be a bit more likely to win.
- There seems to be a whiff of momentum toward Mitt Romney.
I am having a sad. All of that effort, and his two conclusions still have two major errors. Evidently he does not read the Princeton Election Consortium. Let us dissect this.
1. President Obama would be a bit more likely to win. This is false – he’s a lot more likely to win. Look at the Princeton Election Consortium’s EV histogram, which tabulates all 2.3 quadrillion possible combinations of states to give a clear snapshot of the race:
In a race today, President Obama would win with about 90% probability. The true probability is even higher, since the Meta-Analysis does not correct for individual pollster errors. We could – but the political blowback from unskewing polls is too large.
2. There seems to be a whiff of momentum toward Mitt Romney. Ah, yes…Ro-mentum! Bobo has taken the bait. He is probably looking at other aggregators, where for various reasons (q: do you want me to write about that sometime?) the real trends are harder to see. Let’s roll the instant replay.
As you can see, Ro-mentum ended around October 11th, the date of the VP Biden-Ryan debate and reversed around October 16th, Debate #2. Now the median EV expectation is at a plateau around Obama 293 EV, Romney 245 EV. Viewed through the all-important Electoral College, Obama has a Popular Vote Meta-Margin lead of 1.5%. This measure is precise to within <0.5%, far better than any single poll. If anything, the race is starting to look a bit static.
Of course, some change may well happen over the coming 12 days. Based on past races (see “The Presidential Predictor sharpens,” Sept. 29), here is how much movement we can expect.
The “1 SD band” indicates the 1-sigma range for future Meta-Margin change. The election is 12 days away, over which we could expect movement of up to 1.4% in either direction – about equal to the current Meta-Margin. If drift were random, Romney’s chances of catching up would be 1 in 6 – the roll of a die.
But which way will things actually go?
The largest unknown factor that might help Romney is undecided voters. In national surveys ending on Oct. 23 or after, there are still 4.0 +/- 0.7 % undecideds (n=7). Based on past elections (“How will the last holdouts break?” 11/3/2008), undecideds break about equally, with a tiny advantage for the challenger. Romney can expect a net benefit of +0.3 +/- 0.8%. That benefit is a main contributor to the 1 in 6 chance I give him above. However, the uncertainty (0.8%) is larger than the average benefit (0.3%), so it could also hurt him.
In President Obama’s favor, he (a) won debate #3, and (b) has had a Meta-Margin lead of +3.3+/- 1.3% this year. Movement is more likely toward this mean than away from it. The red strike zone in our history graph reflects this, and gives a re-elect probability of 89%.
Don’t be like David Brooks. Finally, a word on examining individual polls. In the comments section, I am seeing breathless statements like how the TIME poll shows Obama +5% in Ohio, and won’t that move the Meta-Margin, and so on. Hey…relax. In case you haven’t noticed, the Meta-Margin’s not moving that much. Try to avoid caressing those individual polls too much!
With that, I end with something in Brooks’s column that I did like:
If you do have to look at polls, you should do it no more than once every few days, to get a general sense of the state of the race.
That’s not bad advice. Instead, spend the time on GOTV in a swing district near you. Here they are.
Finally: in comments, I encourage you to avoid citing individual polls. Give it a try.