October 26, 2004

We Are All Screwed


The other day I mentioned how tight the polls have been.

Now, the increasingly estimable Mystery Pollster points to this, which while reinforcing how tight the race is, also puts a whack upside the head of those of us who've been sweating the tracking polls.
So does it make sense to monitor the daily movements of these tracking polls? The answer is that if you’re hoping to learn something about real trends in support for the presidential candidates, it probably doesn’t make sense. That’s because there is no correlation between the day-to-day movements of the four tracking polls. In other words, they don’t move together—each poll’s movements are unrelated to all of the other polls’ movements. For example, the average correlation between the daily movements of the Zogby Poll and the daily movements of the other three polls is -.18. The average correlation for the Rasmussen Poll is -.07, the average correlation for the TIPP Poll is -.09, and the average correlation for the Washington Post/ABC News Poll is -.12. The combined average for all four tracking polls is -.11. These weak negative correlations mean that there is actually a slight tendency for the polls to move in opposite directions.

What these results indicate is that the day-to-day movements of the tracking polls are essentially random. Rather than reflecting real shifts in voter preferences, the day-to-day movements of the tracking polls are simply reflecting sampling error. This doesn’t mean that the overall results of these polls are wrong. In fact, the average margin between George Bush and John Kerry in the tracking polls has been very close to the average margin in other recent national polls. It just means that the day-to-day shifts in the tracking polls are probably not real and that the real level of support for George Bush and John Kerry within the electorate has not changed over the past few weeks: the presidential race has been very close since the beginning of October and it is likely to remain that way until Election Day.
It's a tie. Jane Galt may pray, but we are all screwed.

Posted by Peter at October 26, 2004 09:43 PM
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