History Makes It Unlikely Debates Alone Will Help Romney Close The Gap

Thomas Holbrook takes a look at the history of pre and post-debate polling and determines that Presidential debates have had little actual impact on the horse race. As Holbrook notes, if debates do have a real impact on the state of the race then we should be able to look at pre and post-debate polling and see an impact of some kind. To start, Holbrook posts this chart of Presidential races going back to 1988:

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   Although the analysis is terribly outdated by now, my debate model from Do Campaigns Matter?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.

Turning attention to 2012, Holbrook suggests that we’re likely to see very little impact on the race from the debates themselves. However, whatever media meme is created by these debates, about either candidate, could very well have a major impact on the next month of the campaign. We’ll have one last round of polling to look at by tomorrow afternoon to give us our final pre-debate snapshot of the race. It will be interesting to see what, if any, impact, these encounters actually have.

H/T: John Sides

FILED UNDER: 2012 Election, Public Opinion Polls, US Politics, , , , , , ,
Doug Mataconis
About Doug Mataconis
Doug Mataconis held a B.A. in Political Science from Rutgers University and J.D. from George Mason University School of Law. He joined the staff of OTB in May 2010 and contributed a staggering 16,483 posts before his retirement in January 2020. He passed far too young in July 2021.


  1. C. Clavin says:

    But, but, but…Romney has been practicing his zingers for two months….

  2. legion says:

    I wouldn’t say they have _no_ impact – Gore’s petulant performance in the 2000 race really turned me (and a lot of other people) off his run – but for this race? Yeah. No “zinger”, no matter how quotable (and no matter how many times Fox runs it on loop) will do either of two important things: change who Mitt Romney _is_ or change who Mitt Romney _appears to be_. Because if “zingers” are all he’s focusing on, then it’s safe to assume that all of his other answers will be just as content-free as they always have been. That’s Mitt’s big problem, image-wise, and it’s one thing he has never shown any interest or ability in changing.

  3. john personna says:

    Wait, is this “setting expectations?” I’m so confused.

  4. anjin-san says:

    It’s worth noting that Reagan’s famous “I paid for this microphone” moment came in a primary debate – voter impressions were far more malleable at that early stage of the game.

  5. K Brown says:

    The most recent polls are disproving historical trends of no bounce post debate.