Election 2008: what really happened

After a quick look at the election results and exit polls (from www.cnn.com), some thoughts:

1. The election was pretty close. Obama won by about 5% of the vote, consistent with the latest polls and consistent with his forecast vote based on forecasts based on the economy.

2. As with previous Republican candidates, McCain did better among the rich than the poor:

But the pattern has changed among the highest-income categories:

3. The gap between young and old has increased–a lot:

But there was no massive turnout among young voters. According to the exit polls, 18% of the voters this time were under 30, as compared to 17% of voters in 2004. (By comparison, 22% of voting-age Americans are under 30.)

4. By ethnicity: Barack Obama won 96% of African Americans, 68% of Latinos, 64% of Asians, and 44% of whites. In 2004, Kerry won 89% of African Americans, 55% of Latinos, 56% of Asians, and 41% of whites. So Obama gained the most among ethnic minorities.

5. The red/blue map was not redrawn; it was more of a national partisan swing. See this state-by-state scatterplot of Obama vote in 2008 vs. Kerry vote in 2004:

The standard deviation of the state swings (excluding D.C. and the unusual case of Hawaii) was 3.3%. That is, after accounting for the national swing in Obama’s favor, most of the states were within 3% of where they were, compared to their relative positions in 2004.

By comparison, here’s the 2000/2004 graph:

The standard deviation of these state swings was 2.4%. This was even less variation–2004 was basically a replay of 2000–still, the relative state swings of 3.3% in 2008 were not large by historical standards.

Again, Obama didn’t redraw the map; he shifted the map over in his favor. (Or, to put it more precisely, the economy shifted the map over in the Democrats’ favor and Obama took advantage of this.)

Here’s the map showing where Obama and McCain did better or worse than expected based on 2004:

6. Finally, how did the pre-election polls do? Unsurprisingly, they pretty much nailed the national vote. And what about the relative positions of the states? The pre-election polls did well there too, at least using Nate Silver’s aggregations. Here’s the scatterplot:

Pretty damn good. The standard deviation of the discrepancies, again excluding D.C. and Hawaii, is 2.5%, which is a big improvement on the 3.3% using Kerry04 alone.

I see some systematic patterns: Obama underperformed where the polls had him way down, and he outperformed where the polls had him up. We should go back and look at these patterns from earlier elections and see if this is consistent. If so, it suggests a way to improve forecasts for next time.

P.S. Age graph fixed from first posting; thanks to Andy Guess for pointing out the error.

97 comments | November 5th, 2008, by Andrew

What will we know on Tuesday at 7pm?

On the evening of November 8, 1988, I was working with my colleague Gary King in his Harvard office. Gary somehow had gotten his hands on a pair of tickets to Michael Dukakis’s victory party in Boston, and we were trying to decide whether to go. Dukakis was expected to lose, but . . . who could say, right? We had the TV on, and the first state to report, at 7pm, was Kentucky, which Bush had won by over 10 points. Gary informed me that the election was over: Kentucky, at the time, was near the political center of America, and there was no way that Dukakis would do much better nationally than he did in Kentucky. So we saved ourselves a subway ride and kept on working.

What about this year’s election night? Can you play along at home with the election and decide at 7pm what is happening? We will perform some calculations using vote margin (as we learned of Kentucky in 1988) and some using only the tally of states won or lost.

I did all the calculations using 10,000 simulations from Nate Silver’s latest election forecast.

At 7pm, we’ll hear from Virginia, Indiana, Georgia, South Carolina, and Kentucky (and also Vermont, which I’ll ignore because of its atypicality). Based on current poll aggregates, we expect the average vote margin in these 5 states to be 5.7 percentage points in favor of McCain.

The top row shows the uncertainty distributions for the popular and electoral vote (Obama wins are shaded in each case). The bottom row shows the corresponding distributions, conditional on the above five states going exactly as expected, with an average McCain victory margin of 5.7 points.

So, if things go as expected at 7pm, it’s all over. But what if things don’t go as expected? The simulations show that the average margin in the five 7pm-closing states could be anywhere from 12 points in favor of McCain to 1 point in favor of Obama. The next graph shows Obama’s expected popular vote margin, electoral vote, and probability of winning under a range of 7pm outcomes.

Finally, we did some calculations based on the scenario in which we don’t know the vote margins but we do know who wins each state. Here’s the story of the key 7pm-closing states:

And then, if McCain wins Virginia, it goes on from there. . . .

See here for the full paper.

5 comments | November 4th, 2008, by Andrew

Are Republicans healthier than Democrats?

Update: See here from Steve Kass. Apparently the researchers below made a mistake in reading the data. That sort of thing happens sometimes–that’s one reason it can be helpful to post things on a blog, so that people can catch mistakes.

My bad in not screening this more carefully before posting. In defense of Subramanian and Perkins, they sent me the paper and it was my idea to blog it. They were planning all along to do more systematic analysis of the raw data (which they haven’t yet received).

S. V. Subramanian and Jessica Perkins write:

The prevalence of poor self-rated health was substantially higher among Democrats (25.8%) as compared to Republicans (8.5%). Lower prevalence of poor health among Republicans was also observed in analyses stratified by poverty, education or race. The prevalence of self-rated poor health among poor Democrats or Black Democrats or Democrats with less than high school education were 3 – 14 times higher than comparable Republicans, suggesting that the observed differences in health status by political ideology may not be due to confounding by race or socioeconomic status:

These patterns remain in conditional linear regression models where self-rated health is modeled as a function of political ideological bent (ranging from strongly Democrat to strongly Republican) adjusted for age, sex, race, marital status, income, poverty, education, smoking and religious affiliation.

We also found that more than twice as many Democrats smoke (16.7%) compared to Republicans (7.1%). The prevalence of smoking among poor, less than high school education, or Black Democrats is 3 to 20 times the smoking prevalence among Republicans (see above).

The observation that Republicans enjoy better health status may reflect the core Republican value of individual responsibility, which could translate into increased adherence to health-promoting behaviors. It is also likely that Republicans tend to exhibit greater religiosity compared to Democrats.5 This could lead to health promoting social conditions, such as enhanced social ties and networks, in part facilitated through increased attendance in places of worship.

Our observations should not be interpreted to suggest that a Republican government necessarily equals better health. It would be erroneous to draw macro inferences based on individual-level correlations. Indeed, the question of which type of political ideology, reflected at the government-level, is better for population health or for reducing health disparities are entirely different queries. At the same time, our findings suggest that certain aspects of Republican ideology may implicitly be health enhancing for the individual. The healthier status of Republicans might also explain, perhaps, why they place lower priority on health care.

Interesting. S.V. said they’re waiting to get the raw data so they can run logistic regressions.

P.S. Let me add a few thoughts based on the comments below and at my other blog:

1. To the extent that difference in smoking rates are that large, this would be a big part of the story. But are smoking rates really so low among those groups of Republicans? Perhaps some mistake? I’d really want to look into this before going further.

2. To the extent that the above (or similar) patterns are actually occurring, I think they’re interesting, even if they’re explained by reporting bias or by experiences or by differences between people in big cities and elsewhere, or whatever. As S.V. noted in his article, differences in perceived health–even if explainable by biases–could result in differences in attitudes toward health policy in general.

7 comments | November 2nd, 2008, by Andrew

Political attitudes of the super-rich

Somebody asked me what I thought of this article by Wall Street Journal writer Robert Frank, “The Rich Support McCain, the Super-Rich Support Obama.” Frank writes,

According to a new survey by Prince & Associates, voters worth $1 million to $10 million are favoring Sen. John McCain, while voters worth $30 million or more are favoring Sen. Barack Obama. The survey of 493 families showed: More than three quarters of those worth $1 million to $10 million plan to vote for Sen. McCain. Only 15% plan to vote for Sen. Obama (the rest are undecided). Of those worth more than $30 million, two-thirds support Sen. Obama, while one third support Sen. McCain.

Do I believe this? Not really. My problem here is that I don’t know where the survey is coming from. How did Prince & Associates sample people making $30 million or more? Without knowing at least something about the sampling, it’s hard to say anything at all about these claims.

For example, a graph accompanying the article linked above gives estimates of about 0.1 million households with over $25 million and 9 million households with over $1 million. This ratio is about 1%; thus, in a simple random sample of 493 people worth over $1 million, you’d expect to see about a whopping 5 people in the survey worth over $30 million. Or maybe there were 6 such people in the sample; that would explain why the percentages of the super-rich cited in the linked article are 16% (1 in 6) and 67% (4 in 6).

The survey might have more than 6 super-rich people in it; I don’t know since no details are given. (I searched on the web for the survey but all I could find were links to the Robert Frank article discussed here.)

How do you take a sample of super-rich people? Prince & Associates is a Connecticut-based consulting company that describes itself as “the foremost empirical research firm in the realm of private wealth. . . Using purposive sampling methodologies, Prince & Associates, Inc. has created statistically valid single-study and panel samples providing detailed insights into the hard-to-reach and exceptionally private universe of the affluent.”

I respect that this sort of sampling is difficult but it’s hard for me to evaluate it when no description is provided of the sample. I’ll email Russ Alan Prince to see if he can enlighten me on this, but really I’d think it would be the responsibility of a Wall Street Journal reporter to ask some questions here. (I guess it’s possible that Frank did ask some questions but for proprietary reasons did not want to describe the sampling methodology, but if so I would’ve appreciated just a sentence or two on it, to give me a little more confidence in the results.)

Other data

The substantive reason I’m skeptical about these findings (as well as a similar report by Daniel Gross in 2004) is the following passage from page 144 of our Red State, Blue State book:

Probably the best evidence [about the political views of the richest Americans] comes from studies of political contributions. Political scientist Thomas Ferguson has tracked political donations of top corporate executives and the Forbes 400 richest Americans (or their equivalents, in earlier periods). The data presented in his 1995 book, Golden Rule, indicate that America’s superrich have generally learned Republican, but with some notable exceptions that have changed over time. Certain industries have persistently higher rates of contributions to the Democrats. In the New Deal, these included industries with a strong interest in free trade. Since the Reagan years, finance, and high technology firms have been much friendlier to Democratic presidential candidates than most of the rest of American business.

For 2004, Ferguson consolidated the lists of top executives and richest families into a lot of 674 firms and investors. Out of this list, 53% contributed to George W. Bush’s reelection campaign and 16% donated to Kerry, with Bush doing better among the oil and pharmaceutical
industries and Kerry getting more from investment banks and hedge funds.

Given that this 53%-16% gap in contributions in 2004, I’m skeptical of the claim that, in 2004, “the haute millionaires, those worth more than $10 million, favored Kerry 59-41.” Which leaves me skeptical of the 2008 survey as well. Perhaps Prince & Associates is oversampling hedge-funders in Connecticut?

I’ll email Prince and let you know if he replies. As I’ve noted above, this stuff is tricky and I’m certainly willing to believe that there is some way by which Ferguson’s and Prince’s results can be reconciled. My guess right now is that Prince’s sample is unrepresentative but I’m open to other explanations.

P.S. Typo above fixed (thanks to commenter).

P.P.S. Tom Ferguson points me to this tally from April of primary election contributions by the super-rich.

1 comment | November 2nd, 2008, by Andrew

Doug Hibbs’s latest forecast

Hibbs writes:

The 3rd quarter data posted by the BEA yesterday are so dire that I [Hibbs] changed my tune and generated a new forecast based on the latest data.

October 31, 2008 update of Presidential Vote Forecast: Preliminary estimates of 2008q3 national income data released on October 30 by the BEA indicate that the economy has weakened so much that I have updated my 2008 election forecast: The Bread and Peace model now predicts a 2-party vote share for McCain of 46.25%, implying Obama will win by a margin of 7.5 percentage points.

Just as a reminder, here’s the graph of Hibbs’s model applied to earlier elections:

As you can see, the incumbent party sometimes loses but they never have gotten really slaughtered. In periods of low economic growth, the incumbent party can lose, but a 53-47 margin would be typical; you wouldn’t expect the challenger to get much more than that. Such things can happen (see, for example, Eisenhower’s performance against Stevenson in 1952) but it wouldn’t be expected.

2 comments | October 31st, 2008, by Andrew

Systematic biases from polling organizations

Len Adleman and Mark Schilling sent along this paper in which they found systematic differences in results from different pollsters:

We compared polls produced by major television networks with those produced by Gallup and Rasmussen. We found that, taken as a whole, polls produced by the networks were significantly to the left of those produced by Gallup and Rasmussen.

We used the available data to provide a tentative ordering of the major television networks’ polls from right to left. Our order (right to left) was: FOX, CNN, NBC (which partners with the Wall Street Journal), ABC (which partners with the Washington Post), CBS (which partners with the New York Times). These results appear to comport well with the commonly held informal perceptions of the political leanings of these agencies.

I guess this makes sense, given that these different news outlets want to make their readers happy. It still surprises me a bit–I thought all these pollsters were pros. It’s not that polling and poll adjustment are easy or automatic–a lot of subjective decisions still need to be made–but I’d think it would be possible to do this without being influenced by your political predilections or those of your audience.

P.S. Some quick comments on the presentation of the results:
- I’d combine tables 2 and 3, and tables 4 and 5.
- I’d remove the second decimal place in Tables 6, 7, 9. Anything less than 0.1 percentage point is both unmeasurable (realistically speaking) and unimportant.
- I’d recommend doing all comparisons relative to the avg of all polls rather than relative to Gallup or Rasmussen. It’s clearer to have a single comparison.
- The x-axis in Figures 2 and 3 are hard to read.
- Table 10 would be clearer as a time-series graph.

5 comments | October 31st, 2008, by Andrew

Clearing up confusion: why we can compute the probability of a decisive vote, even though the election might be decided by a recount

Regarding the probability-of-a-decisive-vote calculation, I’ve received several comments along these lines:

Given the virtual certainty that there would be a recount in a decisive state where the election was very close (not to mention decided by a single vote), and given the virtual certainly that the recount would not yield a second identical result, wouldn’t the true probability that one’s vote would make a difference in both the original count and the recount be many times larger than your estimates? I’m not sure how to calculate that higher probability — but I suspect it would range between 2 X and X-squared where X is the Gelman probability that your vote would be decisive.

My reply: No, that’s not right. See footnote 6 of the article, which points you to p.674 of my BJPS paper with Katz and Bafumi which addresses this issue. The key is that, at some point, the election is determined, and each vote slightly changes the probability of McCain or Obama is winning. Before the election, the exact vote margin is uncertain, and the probability that your vote is decisive must be calculated by averaging over all possible vote margins that might occur. The result is that our calculation works out.

3 comments | October 30th, 2008, by Andrew

Q-and-A

From a recent email interview:

- Why the polls don’t matter while the elections are ‘predictable’? Is there too much confidence in a supposely ‘Obama landslide’?

Based on the economy, Obama was predicted to get something like 53% of the two-party vote.  Due to the U.S. electoral system, if you win 53%, you will win many many states and so the Electoral College will look more like a landslide.

- Do you give any credit to this Bradley Effect?

My guess is that this pattern is less of an issue in a highly contested national election.

- Your book ends with the myth that the rich elite votes Democrat and the poor vote Republican, but does it mean that American politics are in a way a battle of elites (those in the poorest and those in the wealthiest States)?

Yes, U.S. politics is in many ways a battle of elites:  the liberal elites in the Northeast, West Coast, and Upper Midwest, versus the conservative elites in the South and the rest of the country.

- If the image of the poor, religious, gun-loving Republican is a myth, why Republicans keep using the ‘real America’ theme and talk about values of small towns in the middle of the poorest part of the country? Is more a battle of rural vs. urban?

I am not sure here, but I suspect that rural images are popular even with many Americans who live in cities and suburbs.

- And what exactly makes the upper middle class in the wealthier States vote Democrats while their peers vote Republican in other States?

The upper middle class in wealthier states are more likely to be socially liberal (even if they are economically conservative).  In poorer states, the upper middle class tends to be both economically and socially conservative.

- Why the economic slowdown benefits Democrats? Do the richest not share the view that Democrats can handle better economic issues, as the polls generally show, or do they vote against their economic interests? (sort of the opposite that What’s the Matter with Kansas said)

A bad economy makes the current administration less popular among all groups.

- Are race or inmigration the main diving lines? And if so isn’t gonna affect disproportionatelly the Obama result?

Race is a big dividing line, but the line is already there.  At this point, people of all races are reacting to the positions of the candidates and new information.

- I was intrigued by your argument that religion matters nearly as much in European election than in American ones. How could it be when here religion is out of the political campaigns and discourse and there is no question whatsoever about the faith of candidates?

I’m not sure why it’s happened, but the two parties in the U.S. differ much more on social issues than they used to.

- I’d really appreciate your comments. Actually, I liked What’s the Matter with Kansas, but I always felt there was something wrong with the picture, as in Europe the richest tend to be more conservative (althought I also attributed to the fact that, in Europe, Democrats will be probably center-right and Republicans far on the right…). Anyway, thanks to you and your book for the clarification!

I hope this is helpful to you and your readers.  I liked “What’s the Matter with Kansas” also.  That book doesn’t claim to be a statistical analysis.  What it has is analysis of the rhetoric of the Republican party and lots of discussion of the battles within different Republican factions in Kansas.  It’s important stuff.  I think that quantitative studies such as ours and qualitative studies such as Frank’s are both important.

Add comment | October 30th, 2008, by Andrew

Vote for charity’s sake

Here’s the article by Aaron, Noah, and myself on a topic we’ve discussed more formally before: why it makes sense, when voting, to consider the election outcome as it affects the country as a whole rather than just its effects on yourself.

Add comment | October 29th, 2008, by Andrew

Cool basketball graph

Just in case you stumbled upon this blog by accident . . .

Yair made the graphs. See here for his explanation.

Add comment | October 29th, 2008, by Andrew