Really?

This really stinks.

Debate Expectations

With the first debate scheduled for just a few days from now, media attention has begun to focus on what to expect, or not expect, from this year's head-to-head match ups.  Fortunately, it seems that most commentators are on the same page: don't expect much to change because of the debates.  In the spirit of piling on the "debates don't matter much" argument, I'm reposting and updating some of the analysis I presented four years ago on this blog's predecessor.

So the basic idea is that if debates "matter," levels of candidate support should be appreciably different following the debate than they were prior to the debate, presumably shifting in favor of the candidate seen as having "won" the encounter.  This is fairly easy to measure, and I present data in the table below that gives us a sense the magnitude of debate bumps from the last several elections. Here, I compare the polling average from six days prior to the debate to the day of the debate with the average from the seven days following the debate, for all debates from 1988-2008.

These data suggest that the norm is for very little swing in candidate support following debates. Across all 16 presidential debates the average absolute change in candidate support was just less than 1 percentage point. There are a few notable exceptions, of course. Two that stand out are the second debate in 1992, following which George H.W. Bush lost 2 points, and first debate of 2004, after which George W. bush lost 2.26 points. Other debates with above average (but still small) vote shifts are the first debate in 1996, the second debates in 1988 and 2000, and the first debate of 2008. Each of these debates has its own story, and I'm sure we can all think of anecdotes to explain the bumps and wiggles.   Although the analysis is terribly outdated by now, my debate model from Do Campaigns Matter? came to the profound conclusion that the candidate viewed as having won the debate generally gets a small bump. I told you it was profound.

Focusing on single debate bumps may be obscuring a more general, cumulative effect of debates. The last column in the table shows the change in candidate support from one week prior to the first debate to one week after the final debate. Here we see that the debate period generated a 2.42 point bump for George H. W. Bush in 1988; cost Al Gore 3.52 points in 2000; cost George W. Bush almost 2 points in 2000; and John McCain lost almost two points in 2008. Of these debate period swings, the 2000 debates stand out as the most important, especially in the context of the closeness of the election. Part of the explanation for Gore's swoon during the debate period is perhaps related to his performance but another important factor was the media meme that emerged as a result of the debates, including open discussions of whether or not Al Gore was a "serial exaggerator" (see Jamieson and Waldman).  This brings up an important point: it is probably not a good idea to attribute all of the change in candidate support during the debate period to the debates, since there are many other important events, or perhaps even natural drifts in candidate support occurring during these several week periods.

So what does this mean for the three presidential debates this year? I suspect more of the same, which means that neither candidate will probably benefit much from them.  The key factor will be whether one of the candidates can make small gains from each debate that, together, add up to something like a two or three point gain during the debate period.  I'm doubtful, but it could happen.

Don't Count Your Chickens . . .

The most recent (September 19) polling aggregation from Pollster.com shows President Obama with about a three-point lead over Governor Romney.  This, coupled with another bad couple of weeks of media coverage for the Romney campaign, has buoyed the confidence of Obama supporters and has begun to generate a sense of a hapless Romney campaign and an inevitable Obama victory.   Before Obama supporters get too carried away with their euforia, or Romney supporters with their despair, I'd like to remind them both of a guy named Al Gore, who held a fairly commanding lead over George Bush for most the better part of September in the 2000 presidential race:

Note that Gore's lead through about the third week in September was much more substantial than President Obama's current lead in the polls.  Of course, Gore went on to narrowly win the popular vote while narrowly losing the Electoral College vote.  This is not too say I expect a sudden reversal of fortunes in the next couple of weeks.  Just that the current margin really is quite narrow and conditions are still such that a reversal is a real possibility.  Both sides should be anxious; this thing is far from over.

Poll of Forecasters

Jim Campbell has assembled a list of several forecasts that will appear in the October issue of PS.

Here it is.

Forecast

Now that I have final summer data from the Survey and Consumers I can generate a forecast from my National Conditions and Incumbency model.  The gist of my model is that the incumbent presidential party is held accountable for prevailing national conditions but that the level of accountability depends upon whether the incumbent president is running for reelection.  Granted, the idea that the president's party is punished or rewarded based on prevailing conditions is hardly revolutionary.  Where my model departs from most others, though, is that it incorporates incumbency as a conditioning variable, with the expectation that national conditions are stronger predictors of election outcomes when an incumbent president is running.  Note that I'm not saying conditions don't matter in open seat contests; just that they matter more in incumbent contests.   National conditions are measured here with an index that takes into account the level of presidential approval (Gallup) and aggregate levels of satisfaction with personal finances (Survey of Consumers), both averaged over the summer months of the election year.   You can access a copy of my paper here.

The key Figure is posted below:

Figure 1. National Conditions and US Presidential Elections, 1952-2008

As this figure illustrates, national conditions track much better with election outcomes in years when the incumbent president is running than in open-seat contests.

So what does all of this mean for the 2012 election?  Right now the national conditions index (explained in greater detail in the paper) stands at 63.3.   This is the fifth lowest reading from the fifteen elections presented above, and the third lowest of the nine elections involving an incumbent. Based on this value for national conditions, the forecast for the 2012 election is 47.9% for President Obama and 52.1% for Governor Romney.  

I'd like to be clear that the national conditions index for 2012 points a less-than-ideal situation for a sitting incumbent, but it does not suggest that conditions are so bad that the challenging party can coast to victory.   Consider the years in the sample for which the national conditions index had a lower value than the current year: 1952, 1980, 1992, and 2008.  These were all really tough years for the incumbent party, and it is easy to see why when considering the prevailing conditions in those years.  I see 2012 as somewhat different.  As I say in the paper, given the small sample of elections, and the size of the out-of sample prediction error, this points to a tight race but one where Governor Romney is the favorite.

Bump Time

With the major party conventions kicking off next week it's time to return to one of my favorite topics, conventions bumps.  Four years ago, I posted a summary of convention bumps and I'm updating that information here so we can get a sense of what to expect this year.

I measure convention bumps as the percentage point change in the convening party's share of the two-party vote, comparing polls taken between six days and two-weeks prior to the convention with polls taken during the seven days following the convention.  Note that this is a short-term measure of the convention bump and does not say anything about the rate of decay in the weeks following the convention.  The figure posted below summarizes the convention bumps for both the Republican and Democratic nominees from 1964 to 2008.

The first thing to note is that there is a lot of variation in convention bumps. Fortunately, as I showed in Do Campaigns Matter?, there is a systematic component to that variation. Two things in particular seem to drive the size of the bumps. First, candidates who are running ahead of where they "should" be (based on the expected election outcome) tend to get smaller bumps, and those running behind their expected level of support get larger bumps. In this way, the conventions help bring the public closer to the expected outcome and help to make elections more predictable. A perfect example of this phenomenon is the 1964 conventions. Goldwater got a huge bump, in part because he was running 16 points behind his expected vote share, and Johnson got no bump, in part because he was running 6 points above his expected vote share prior to the Democratic convention.  For the years presented above, the correlation between how far ahead of the expected outcome (based on an election forecast) a candidate is running in pre-convention polls and the size of the convention bump is -.42.  While all candidates may want to get a big bump from their convention, big bumps are not always a good thing; they could signal that the campaign is not doing as well as expected.

Timing also plays a role in explaining convention bumps.  When I first started looking into this (1996) there was a tendency for the party holding the earliest convention to get a larger bump.  This made sense for a couple of reasons. First, it is the out-party holding the earliest convention and people usually know less about the out-party nominee, since the incumbent party almost always runs an incumbent president or vice-president (John McCain being the most recent exception).  In addition, historically the first convention had been held sometime in late July or early August, a time period when there might be more undecided voters.  Importantly, the tradition at the time was that the in-party convention would usually be held three to four weeks later, which gave time for the message from the first convention to resonate.  However, in 1996 and 2000 the conventions were held fairly late and only two weeks apart.  And, more recently, the 2008 conventions were held in back-to-back weeks in late August and early September, creating a situation in which the messages of both campaigns no doubt interfered with each other.  This, of course, is also the timing of the 2012 conventions. When taking these changes in timing into account, it turns out that the number of days a convention is held before or after¹  the other party's convention is a stronger predictor of convention bump (r=.37) than simply going first (r=.22).  Of course, the "days between conventions" measure captures both how early the first party convenes and how close together the conventions are.

Finally, it also appears that there is a general trend toward smaller bumps in the last few elections cycles, though this could simply reflect the changes in timing of the conventions.  Truly large bumps were somewhat common prior to 1996 but have not made an appearance since then.

Taking all of these factors into account, and adding a dummy variable to control for the disastrous Democratic conventions of 1968 and 1972, we can see that there is a predictable element  to convention bumps:

                      

This is not to say that there aren't interesting and unique aspects of every convention that might explain why the convening party over- or under-performs the expected outcome--just that, by and large, the pattern of convention bumps is explained by a few simple variables.  The correspondence between predicted (by the model shown above) and actual convention bumps illustrates this point quite well:

               

Generally, conventions expected to produce large bumps tend to do so, and those predicted to produce small bumps also fit the pattern.  What's important to note, though, is the the pattern is far from perfect and some of the larger deviations from the from the predicted outcome make sense, given what we know about those specific conventions.  For instance, the Democratic convention of 1984--a convention plagued by in-party fighting--underperformed by a little over five percentage points, while the Democratic convention of 1992--one that benefit from Ross Perot dropping out of the race and near-endorsing the party's nominee, Bill Clinton--exceeded expectations by almost six percentage points.

2012 Bumps

So what does this all mean for the conventions coming up in the next two weeks?  I won't have complete data for the Obama bump prediction until the opening days of the Republican convention, and my general election forecast (used in the model) is preliminary at this point (I will post that model when all the data are in; preliminary data point to narrow Romney win).  But I don't expect any of the data to change dramatically in the next few days, so I will go ahead and make a prediction for the 2012 convention bumps:

Predicted Romney Bump:    3.6 percentage points
Predicted Obama Bump:      1.1 percentage points

Right now, the two candidates are in a tight race, with Obama holding a slight advantage in the polls.  Based on my bump predictions, I expect that the race will continue to be tight after the conventions but that Romney will hold a slight lead.

Huge caveat: Hurricane Isaac.  I have no earthly idea how a hurricane-shortened convention will afect things, though I suspect it would not be good for the Romney campaign

¹So, the first convention gets a score equal to the number of days it begins before the first day of the second convention, and the second convention gets a score equal to the number of -1 times the number of days it begins after the last day of the first convention. 

Ryan Reaction

Here.  (I didn't pick the headline).