Daily Fluctuations in Polls

Regular readers may have noticed that, while I will comment on them from time to time, I write far less about the polls than many other political blogs. While the overall trend showing that Obama has a possibly insurmountable lead (at least based upon past elections at this stage), the day to day changes are not as significant as many make them out to be. A good example can be seen in the Gallup daily tracking polls.

Last week Obama had gone up by as many as eleven points. Suddenly he had a day yesterday in which he was only up by seven and some were using this to claim that John McCain was making a come back. More likely it is just part of the daily noise in the poll which is not precise enough to mean very much on a day to day basis. My discounting of yesterday’s result was verified today, with Obama back up by ten points. Other polls are showing similar results, such as a Washington Post-ABC News poll also showing Obama leading by ten.

These day to day variations do not mean much, unless there is a sustained trend. Even an upward move by McCain does not mean that the fundamentals of the race are changing. It is common for a politician who trails by this much to close the gap by election day. It is highly unlikely for a candidate this far behind to actually win. Hubert Humphrey came back from twelve points behind, but still wound up losing a close election. If not for butterfly ballots and a blocked recount in Florida, Al Gore was almost an exception in coming back from seven points behind, but Gore did not have the obstacles of an ever greater deficit and tremendous sentiment to throw out the governing party.

This is not to say that it is impossible for the race to change, but it will take some major news and not more of the same attacks from McCain. The only case where a candidate came back from a deficit of anything close to this size was Ronald Reagan, who was behind Jimmy Carter 47% to 39% on October 26. In this case the debate wasn’t until October 28. McCain is unlikely to accomplish what Reagan did as in this case Barack Obama is the candidate in the Ronald Reagan role, having already reassured voters who seek a change in government that he is up to the job in earlier debates.

Something we don’t anticipate might still happen, and the number of presidential elections which had contests in which both candidates had a realistic chance to win do make up too small a sample to predict anything with certainty. Still there is enough history to safely predict that only major news can shake up the race and a change in the polls from one day to the next means very little.

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