Princeton Election Consortium

Innovations in democracy since 2004

Outcome: Biden 306 EV (D+1.2% from toss-up), Senate 50 D (D+1.0%)
Nov 3 polls: Biden 342 EV (D+5.3%), Senate 50-55 D (D+3.9%), House control D+4.6%
Moneyball states: President AZ NE-2 NV, Senate MT ME AK, Legislatures KS TX NC

The mailbag

September 30th, 2012, 12:00pm by Sam Wang

If you are a casual reader, you might be missing out on some very good comment threads. This year they include physicists, political scientists, lawyers, financial traders, neuroscientists…there’s a lot going on down there. Many are partisans, but the emphasis is on analysis, not political opinion.

A recent sampling follows.

Often I express the idea that rational campaign donation involves identifying knife-edge situations where the outcome could go either way – this year, the House and certain Senate races (ActBlue) (Crossroads GPS). However, Till makes an interesting counterpoint.

…a race becoming less competitive…may not be symmetric, because there are also incentives for an important group of donors to support a candidate who is clearly winning, especially if they were previously supporting the other candidate. It all depends on whether someone just wants a candidate to win, or whether someone wants something in return from the candidate. There may in fact also be an incentive to support a candidate whose chances are very slim, because the number of other supporters competing for favours from the candidate will be reduced (an example being Foster Friess donating to Rick Santorum during the primaries: Santorum’s chances were always small, but this meant that Friess was the single most important supporter). All of these effects may be small compared to the “anonymous rational” supporter seeking to have the greatest impact on the race itself, but they may suggest that just “following the money” to infer perceived probabilities is not as simple.

I had thought that it would be in the Democrats’ interest to win the House, which is a strict majoritarian chamber. I worked as a staff member there, and I came to think of it as a big game of Calvinball, where the majority makes the rules. However, Ottobvs thinks there are advantages to not holding a narrowly divided House:

In strictly political terms, if the Republicans hold onto the House but with a very narrow majority, say single figures, this could be the best outcome for the Dems because it locks the Republicans into responsibility for governing. There’s much legislation that has to be passed and Boehner will need Democratic votes to pass it and will be forced to compromise on a lot of Republican ideology. This is going to cause mayhem in the GOP.

One gamblin’ man, Patrick McL, grasps that a 74% probability of the House flipping is really not all that high at all:

Yes, that number feels to the human gut like a high probability.

But what it’s saying is that based on the *math* (guts don’t do math), the odds of the GOP retaining the House is equal to flipping a coin twice and getting heads both times. That’s really not all that unlikely an outcome.

This is, broadly speaking, just a careful examination of what electoral coattails mean….And it makes sense when you think of it that way. The larger Obama’s coattails (or the larger the cratering of the GOP ticket at the top…), the more marginal GOP voters will just stay away. Why vote, when they know Obama will pound Mitt in their state? The slightly less marginal voters–who follow senatorial candidates–who see the GOP candidate in their state in the same light (either a clear loser anyway, or perhaps so toxic…), the more they’ll just stay away.

Widen the margin enough….Human psychology will bring out more who want to vote for their winning candidate. The down-ticket impact only grows. So we’re at–what Sam’s math tells us, not our guts–the point where any tails result in two coin tosses gives the Democrats the House. That may or may not make you happy, but it is the math.

Another, JaredL, says:

As a poker player, at least before online poker got shut down, it’s easy for me to see that 74% is no lock. It’s about the odds of winning with AK when your opponent has KQ. Put in non-gambling terms, 26% is just a bit more likely than tossing heads twice in a row. If you regularly toss coins, you wouldn’t be at all surprised if that came up.

And that’s just a sampling. Other regular commenters, too many to name, keep it lively and insightful. Thank you all.

Tags: Site News

29 Comments so far ↓

  • Olav Grinde

    In my opinion, one of the best aspects of the comment threads is that Dr Wang takes the time to respond, offer enlightening counter-arguments, post additional information and good links to other experts, and patiently provide lucid answers to questions.

    All reasons why this is the best election prediction site out there!

  • A. Sood

    I’m not sure I agree with the statement “Human psychology will bring out more who want to vote for their winning candidate.” If that were true, than shouldn’t the winner tend to outperform their final polling average? It doesn’t seem to me that that is the case. (see: ’72, ’76, ’84, ’88, ’92, ’96, ’00)

  • Billy

    Sam, thanks for making a great site. I got tired of reading 538 earlier this year because it all felt the same (plus the seemingly arbitrary interpretation of daily polls and how it affected the forecast), but you manage to bring in fresh content with lots of sound technical information to support your arguments. Keep up the good work!!!

  • wheelers cat

    I think its even better than that.
    “Wild” (as in undomesticated) analysis and emergent paradigms.
    Guerilla thought.
    PEC is the leading edge of the wave.

  • DaveM

    I enjoyed 538 four years ago, finding it (and then PEC) to be calmly credible amidst the din (when the Palin-inspired McCain bounce evaporated as prophesied, my electoral anxiety gave way to my fascination with the horse race). But a big part of what made 538 work for me was the discussion, now cloistered behind the NYT paywall and the time-lapse moderation. Discussion here is free and open and, therefore, lively in a way that’s no longer the case at 538.

    The Times’ protocols have deadened the feel of 538 in other ways, as well. Scrupulous avoidance of any partisanship in the writing–Nate was already inclined that way, but the old site leavened that with Sean Quinn’s behind-the-scenes travelogue pieces–seems stilted somehow, compared to the entirely natural way Sam and others here acknowledge their preferences without (by and large) detracting from their analyses.

    The biggest (non-methodological) reason I prefer this site is that PEC doesn’t require Sam to refer to Mr. Romney and Mr. Obama.

    • Some Body

      I wouldn’t say comment here is free and uninhibited. This is the third time I’m trying to post a comment here, with substantive (perhaps not very bright; it’s not for me to judge) remarks or questions, no foul language or anything like that.
      The two previous attempts never made it to the comments page (and I doubt it that this one will either). It never transpired to me why. But when a comment section is being moderated this way, you get the feeling that the commenters are some sort of exclusive club. IMHO, that’s not the way websites open to the public are meant to work.

    • Sam Wang

      Sorry you feel that way. It is true that I sometimes shape the discussion. I often remove excessive expressions of pure partisan opinion. DailyKos and HotAir are good homes for that kind of thing. It helps to leave a real address.

    • Olav Grinde

      DaveM: “…compared to the entirely natural way Sam and others here acknowledge their preferences without (by and large) detracting from their analyses.”

      I wholeheartedly concur. That’s intellectual honesty! But on this occasion I can’t resist quoting Stephen Colbert: “As we know, reality has a liberal bias.”

    • MAT

      IMHO, I wish more websites moderated comments. I’m of the firm opinion that if one allows commentary, then you ‘own’ or are responsible for the results ( note how many Facebook comment threads race straight for the bottom when a little judicious pruning would do wonders for everyone’s blood pressure).

      Moderation of comments, if done appropriately, can greatly enhance the value of the overall product by weeding out noise. While of course I’m not seeing what comments Dr. Wang has filtered, he’s made a very real effort to respond to posts thart have disagreed or questioned his methodology. If the price of admission is having something worthwhile and on topic to say, then please, keep the bar set high. I have standards for discussion in my home, it seems reasonable for someone to have standards for their website.

    • Some Body

      Sam – well, that’ s definitely a legitimate policy (and a good one too; keeps the discussion on topic), but it would have been better to state and explain it clearly where commenters can see it.
      It still keeps me in the dark about my own comments, though (which had no partisan opinion expressed in them at all), so there must be some other criteria for screening comments out. Well, these had better be stated clearly too.

    • Matt McIrvin

      Sean Quinn’s travelogues giving an on-the-ground picture of the election campaign were the best thing about the old 538 site. I really miss them.

  • Amitabh Lath

    Sam, I believe your site has made a lot of people think deeply about measurements, uncertainties, probabilities, mean vs. median, etc. Not just people like us who like it, but narrative-minded people as well.

    In simple classical mechanics, you can solve a large class of problems by invoking energy conservation. In doing so, you lose the time-dependent information. In other words, you lose the narrative information, but get to the final answer.

    Similarly, many writers/bloggers want narrative type information. They want to know about western Ohio and northern Virginia and wither Missouri and all that.

    You meta-analysis sums over all that. Gets to the final number without worrying about who wins what.

    And I can’t emphasize this enough: error bands.

    • Matt McIrvin

      These days, though, the state-by-state picture is actually so simple that you can often read the story directly off of the computed probability distribution! It’ll be dominated by a big spike that just gets doubled or quadrupled by the daily uncertainty in Florida or in Virginia and NC, in a way that reminds the people with physics training of quantum-mechanical spectra.

  • Dave Kliman


    This is indeed the site I go to to make the most sense of the data. It was painful to watch, as a democrat, in 2004, but 2008 and this year have been a very comforting alternative to the misleading and often histrionic ramblings of the main stream media, which I do try to avoid paying attention to, as a matter of habit.

    Also, your taking the time to write posts regularly adds a lot of extra value to what this site might be with merely the data and the charts alone.

  • 538 Refugee

    Right now 538 projects Obama to receive 319.3 electoral votes. I’ll bet EVERYTHING I own, can borrow or steal that this prediction will not come to pass. Any takers?

    Really, at some point the tinkering is just too much as are the explanations as too why this and that is being fudged and factored. Nate should be spending a little time tinkering with his model so that it spits out real numbers instead.

    • Matt McIrvin

      Well, obviously Obama won’t receive 319.3 electoral votes as it’s impossible to receive 0.3 of an electoral vote, but for all the quibbles one might have with Nate’s model, I don’t see the point in criticizing it for giving a probabilistic average.

    • wheelers cat

      protip for you, 538 refugee, and pechmerle and any others nostalgic for the old Nate– check out his twitter stream–
      Nate shows a lot more intellectual honesty in 140 chars or less….praps NYT pays by the word.

  • wufwugy

    NYT has weakened Nate’s brand and there are too many mouth-breathers in the comments. As long as Sam continues to keep it real, this will be the premiere blog for poll analysis. Part of me hopes that PEC could branch out into more related political examinations, but perhaps that wouldn’t be best. Who knows

  • pechmerle

    I don’t miss the reader comments pages of the old 538 of 2008. Yes, there were insightful comments along the way — but mixed in among vast — truly vast — quantities of purely partisan ranting. That got old, and wearing to wade through to see the good stuff.

    Nate did do a good job that year of responding to the meaningful reader comments.

    This year, I don’t have to care how he’s doing because — thanks to PEC — I have all the information I really need to be comfortable ignoring almost all of the horse race color commentary.

    Though who of us on the liberal side could fail to enjoy this on Friday: ‘Ann Romney told a Nevada television station her biggest concern if her husband, Republican presidential candidate Mitt Romney, becomes president was his “mental well-being.”‘ Happily (for some), the numbers suggest the poor man will be spared all that stress.

    • wheelers cat

      I wonder if one could regress Romney’s unfavorability index on twitter trends.
      As soon as the news story emerges that Romney is preparing “zingers” for the debate #romneyzingers takes off.

      “Mr. Romney’s team has concluded that debates are about creating moments and has equipped him with a series of zingers that he has memorized and has been practicing on aides since August. “

  • Ms. Jay Sheckley

    Re the Senate & House race, something unusual is happening. If you search _public_ Facebook posts for Congress [your friends may be biased; scroll from the bottom for a hefty, ongoing sample] I find that those posts concerning American government seem to favor the left at greater than a two to one ratio. I don’t think you need to be signed up to try it, this is all public. Of course it is possible that more support in favor of the GOP is kept private.
    I see something unusual happening. For years we’ve seen suggestions to vote straight party line, but the vehemence and specific mentions of congress this year lead me to believe that some voters are going to the polls specifically to participate in what I see called coattail and down ticket races. I think there’s been a change since 2010 to the point where perhaps future presidential year polls will ask if people would vote just for congress this year. Here is the only poll I found addressing the point but it is an interesting one. I think we can trust Dr Wang that if the House race were a weather report, you might be sorry if you didnt carry an umbrella.

  • Tim

    I agree with the theme of independence in these comments regarding this blog. 538 seems to have become absorbed in the mammoth workings of and become neutered. (Even though Nate is still quoted everywhere). I’m an English professor and don’t do numbers,but I must say you guys make stats very cool. And I’ve said this before, our country craves and needs a revival of empiricism, especially given its unpopularity and inconvenience in some political quarters.

  • Chris Miller

    Sam, no need to publish this, but I just wanted to thank you for a great site. I only discovered you within the last couple of weeks, but I find myself coming back every day to see what’s new.

  • Amitabh Lath

    538 Refugee writes: Right now 538 projects Obama to receive 319.3 electoral votes.

    This really really gets my goat.
    No error bars = repeat the lab.

    If you publish a result to four significant figures, without uncertainties, then you are asserting that you it to that precision. And no, he does not know the electoral vote total to a tenth.

    If you look at say, a week of jitter in the 538 ‘casts, you can estimate an uncertainty (unless you believe those fluctuations are real…).

    • Matt McIrvin

      Silver does better than showing error bars or following “sig fig” rules, though: he’s got a graph of his entire probability distribution right on the page, much like Prof. Wang. One can criticize his calculated distribution, but I think he makes it pretty clear that that central number is just an expectation value calculated from the distribution.

  • Matt McIrvin

    …actually, it’s a little different, in that Silver attempts to show a distribution for his actual November prediction, whereas PEC only gives that for the equivalent of a “now-cast” and provides error bars for the prediction.

    • Amitabh Lath

      The prediction for Nov 6 is from a model that has economic data, unemployment, etc. added in. To get real uncertainties from his Monte Carlo method he would have to assign uncertainties to those variables, along with any correlations they might have with other variables (like poll numbers).

      I agree that the sigma on his “Now Cast” can be eyeballed from the distribution of simulation results. To get error on the mean (sigma/sqrt(N)) you would have to know how many polls contributed.

  • Mark

    wonderful read, thank you so much for the educaton, sincerely.

  • Philip Diehl

    Aren’t the odds of a House flip only half the equation a rational bettor would use to decide whether or not to place a bet?

    If I were to conclude that there’s a 74% chance that the Democrats will win control, but I could place a $2 bet on Intrade to win $10 (today’s price), wouldn’t I (a rational bettor) place the bet?

    What am I missing?

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