Lately, I have been spouting off about how undecideds tend to break about 60% for the challenger and 40% for the incumbent in the final week of the campaign. I was basing this off of a quick estimate from research I had done five weeks ago. However, I had never actually sat down and crunched the numbers to truly determine the average undecided swing in the final week of a campaign in elections involving an incumbent. Now I have, and that is one Friday afternoon and evening that I will never get back.
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%