Notes on Poll-Watching, as Shift Toward General Election Season Begins
In a couple of weeks, we’ll be starting our FiveThirtyEight forecasts for the general election. But there’s still a fair amount of work to get those ready, and we seem to be seeing an increasing number of head-to-head polls pairing President Obama against Mitt Romney in the meantime. Thus, as we transition into general election season, I wanted to articulate a few quick reminders about the philosophy I take toward looking at these polls and other important pieces of general-election related data.
1. Be patient. Many of the poll-watching habits you learned for the primaries you will need to unlearn for the general election.
In the primaries, it is often worth paying a tremendous amount of attention to how recently a poll was conducted. Because voter opinion shifts rapidly in primaries, a poll that is even two or three days old might have substantially less information value than one that was released today.
That just isn’t true in the general election, when there are fewer swing voters, the candidates are better known, and voter preferences are more rigid. Instead, polls have a much stronger tendency to revert to the mean, and what is perceived to be “momentum” is often just statistical noise. In October, it might be worth sweating just a little bit if there seems to be a two- or three-percentage point shift against your preferred candidate. Right now, it probably isn’t; a poll released on April 20 isn’t going to be much better in the long-run than one released on April 10.
2. Take the poll average. This ought to be obvious, but you should generally be looking for a trend to show up in several different polls from several different polling firms before you start to view it as newsworthy. Again, this differs a little bit from the primaries because there is less of a premium on recency in the general election; you’re usually better off waiting for another (or better yet two or three more) data points.
The easiest way to do this is to take an average of recent polls, as sites like Real Clear Politics do. The technique that
You can read the rest of this article at:: http://fivethirtyeight.blogs.nytimes.com/2012/04/16/notes-on-poll-watching-as-shift-toward-general-election-season-begins/
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