Incumbent Rule Research Update
by Chris Bowers, Fri Sep 03, 2004 at 06:29:04 PM EDT
Using my own research as well as research sent to me by Nick Panagakis of the National Council on Public Polls, I have gone through 451 poll results since 1976. In all 451 cases, the poll was in the field for at least one day that was within seven days of the election. In every case, it was the final poll taken by the polling firm for the campaign in question. Also, I do not believe that any internal or partisan poll results were used. Unfortunately, outside of the Presidential race, I was severely lacking in data from 1996.
My methodology worked as follows:
- 1. Subtract the final poll result for the incumbent from the actual election result for the incumbent to determine the total number of points the incumbent gained from the final poll until the election. Total all 451 of these results to determine the total number of points all incumbents gained from all final polls until the election.
- 2. Subtract the final poll result for the challenger from the actual election result for the challenger to determine the total number of points the challenger gained from the final poll until the election. Total all 451 of these results to determine the total number of points all challenges gained from all final polls until the election.
- 3. Take the total from step #1 and add it to the total from step #2. Divide this total into both the result from step #1 and step #2 to determine the relative gain for the incumbent and the challenger.
Year Polls Und. Inc. Chal. President 28 2.4 14% 86% 1976-88 155 11.8 20% 80% 1994 101 11.2 35% 65% 1998 76 10.1 27% 73% 2000 31 8.6 40% 60% 2002-4 60 7.5 42% 58% 1992-04 283 8.9 34% 66% Total 451 9.7 28% 72%Here are my first thoughts on this data:
- Is the incumbent rule weakening? With the exception of 1998, where Democrats kicked ass on GOTV, it has been a slow progression toward parity. Then again, this chart has holes, such as a complete lack of polls from 1996, which prevents one from drawing such a conclusion with confidence.
- The number of undecided voters is clearly going down. This year, I see no reason not to expect more of the same. As the two parties slowly become primarily ideological, rather than regional and ethnic coalitions, the difference to voters is becoming starker. As a result of this, more people have made up their minds going into the booth. We really are becoming a polarized nation--that isn't just pundit bullshit.
- The Presidential sample stands out for its extremely small movement from final polls until election night. Even though undecideds break overwhelmingly--better than 6 to 1--in favor of the challenger in a Presidential race, pollsters seem particularly adept at national trial heats in Presidential races. Probably because of the extreme amount of national attention given to the Presidential race, far more people have made up their minds going into the booth than in other elections. While we should not expect significant movement from the final polls on November 1 to the final results on November 2, whatever small movement there is will be almost entirely for Kerry.
- Considering how accurate polling firms tend to be in national elections, in my presidential projections I will now include likely voter models from polling firms that do not include registered voter models. Where available, I will still use the registered voter models until the final week, however. Also, I will only include trial heats that push leaners, and give 80% of the remaining undecided to Kerry. There is simply no way that even 5% of the country will be truly undecided between Bush and Kerry going into the booth.
- Should the 1992-2004 average of 66 to 34 in favor of the challenger, or 2 to 1, be considered a benchmark at which point GOTV efforts make the rest of the difference? At least for now, I'm going to run with this possibility.