Princeton Election Consortium

A first draft of electoral history. Since 2004

VP debate: big audience but race unchanged

October 5th, 2008, 3:00pm by Sam Wang


Biden v. Palin drew 70 million viewers, one-third more than Obama v. McCain. VP debates usually don’t matter, but I wondered…

It’s hard to tell because of the ongoing post-debate surge for Obama. When events come so dense in time, it’s unclear what is really game-changing. For instance, on Sept. 24th, John McCain “suspended” his campaign. This has been dinged by Barron’s as being a critically bad event. On the 26th the first presidential debate occurred. All throughout was the ongoing economic crisis. During this period tracking polls showed a strong surge for Obama. Could there be said to be a single triggering event?

Recall my deconvolution of Gallup Daily‘s 3-day moving average, in which I use the principle of variance minimization to extract single-day results (MATLAB code available here). Around the time of the first debate it gives

Date Obama 1-day McCain 1-day Difference Event
9/22 46 45 Obama +1%
9/23 47 47 tie
9/24 45 46 McCain +1% McCain suspends
9/25 52 42 Obama +10%
9/26 50 44 Obama +6% Debate #1
9/27 48 40 Obama +8%
9/28 52 42 Obama +10%

Assuming these numbers are correct, a 9-point swing or larger is significant (P<0.05, two-tailed). The 11-point swing from 9/24 to 9/25, which was sustained on 9/26, suggests that McCain’s suspension had an unintended bad effect for him, one that was maintained by the Friday debate. Or perhaps we should think of the two events as being a single event in the minds of voters.

There’s no visible bounce at all after the VP debate:

Date Obama 1-day McCain 1-day Difference Event
9/29 47 47 Obama +1%
9/30 45 43 Obama +2%
10/1 52 39 Obama +13%
10/2 50 44 Obama +6%
10/3 50 44 Obama +6% Debate #1
10/4 48 43 Obama +5%
9/28 52 42 Obama +10%

…which suggests that if the VP debate did move opinion, it’s not detectable this way. There’s a +11% event on 10/1 for no clear reason, which might be noise. The original average tells us the same thing, as does the EV estimator.

Of course, polls are not the only measure of a debate. Debates are also among the few chances we get to hear about opposing policies and plans, side by side. Also, as I wrote before, Palin’s performance may have rehabilitated her image with GOP base voters, many of whom liked what they saw. Regardless of whether they would be better off taking their party in a different direction, if McCain loses Palin’s a contender for the 2012 nomination .

Tags: 2008 Election · Meta-analysis

5 Comments so far ↓

  • Rex Douglass

    I enjoyed this post, and the talk you gave to the politics department the other day. A nagging question I still have though is how we can pick which event to assign to violent swings, particularly when there is a lot going on at the same time. For example, it seems far more credible to assign the swing to Obama not to McCain’s suspension of the campaign but the media coverage of the economic crisis for which the GOP/McCain gets blamed. His suspension was in fact a strategic move (though desperate) to try to get ahead of the thing that would drop his poll numbers not the cause of the fall in poll numbers. Picturing the campaign as a strategic interaction might help to assign poll shifts “further up the tree of events.”

  • Dave

    The only rhetoric uttered by politicians and pundits alike before the VP selections were announced was that VP nominees ultimately make no difference in the election.

    1. The nonstop, round the clock coverage of the VP front-runners, however, seems to contradict this belief. The further post-VP debate dissection and analysis, as well as the enormous interest in the VP debate, seems to contradict it even further. Are there any published studies regarding the effect of VP selections and election outcome? If there is, I’m sure it’s based on scant data.

    2. Regardless of your party affiliation, I find it hard to believe that any honest (educated) person finds Palin remotely qualified to be president. When I was growing up, we wanted our leaders to be better educated and better informed than we were. Instead, Palin is the epitome of what has gone wrong in the Republican party: her pretty face and folksy demeanor is only a thin veneer for the aggressive, religious extremism that has gripped the party. Sure there were pro-choice/pro-life debates during the Reagan years, but never has the religious right threatened to take over the Republican party with which I used to identify so closely as much as it does now. It is a shame that John McCain isn’t maverick enough to truly run on his principles, and has allowed himself and the campaign for the highest office in the world to be hijacked by a bunch of nutcases.

  • AlanJae

    “Joining with Bush, Reid, Pelosi, and Paulson is the opposite of mavericky.”

    Perhaps we could just coined a new term:
    ‘maverickicity’ – the measure of one’s ‘maverickness’.

  • dseiple

    Well I’ll be voting for Obama, and now that that’s out of the way, I’d like to agree with jbarntt that McCain “won” the first debate — if you judge it as a debate. I had houseful of people who left depressed because of this. However, what we didn’t realize till later was that for many voters, this wasn’t a debate — it was an audition for whom they want to be listening to from the Oval Office. They don’t like McCain, period.

    Franky, I came off liking him better than I had since his 2000 run (when I really was rooting for him), but for the still-swing voters who, I guess, haven’t been paying attention to the debating points themselves (or they’d have their decision by now), it’s just too late. And the recent turn to the gutter by the Republicans (Bill Ayers AGAIN?!) is likely to strike these crucial voters as a repudiation of what used to be one of McCain’s strongest assets. That’s quite a change, and the voters are saying: “That’s not the change we need.”

  • jbarntt

    I’ll be voting McCain, just to get that out of the way.

    I thought it was dumb of McCain to suspend his campaign and I’m not really even sure what it means to do so. Politically, I didn’t understand why it was good to join up with all the big players in DC to get the bailout passed.

    I thought a smarter political move would have been to oppose it and support one of the other proposals, such as Peter DeFazio’s, (D-OR). Joining with Bush, Reid, Pelosi, and Paulson is the opposite of mavericky.

    I did think McCain was overall better in the first debate, but it was a win on points and Obama seemed credible as the next pres., which means a small win for Obama.

    Palin did fine in her debate and probably quilled some doubts, but despite some odd statements, Biden did not lose his “better qualified to be pres. than Palin”.

    Anyway, veeps and their debates rarely make a big difference.