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The Democratic Strategist

Political Strategy for a Permanent Democratic Majority

Averaging Horse Race Polls Gives Best Snapshot

With the presidential election 17 months out, it may seem a little early to be paying a lot of attention to the horse race polls. But Super Tuesday is 8 and 1/2 months away, and that seems a good time to begin monitoring the Democratic polls. To put the polls in perspective, start with Chris Bowers’ post, “Inflated Clinton Poll Theory: Prudence Sets In” at MyDD. Bowers argues that averaging polls gives the best snapshot:

With so many polls, it just seems unlikely to me that one extreme Clinton-Obama margin or the other is absolutely correct, or that one methodology or the other is absolutely correct. When has there ever been a large, hidden vote out that that most pollsters were missing? Outside of the Iowa caucuses and post-Katrina New Orleans, the answer over the last thirty years has been “basically never.” These days, the worst-case scenario is for poll averages to be about six points off the final margin, which isn’t that bad and can be accounted for in margin of error and turnout programs.
…At this point, with so many different polls floating around, with so many different methodologies, with about half of the primary and caucus electorate not even paying “somewhat” close attention, and with an ever-changing and developing campaign, the simple fact is that widely varying results among polls is unavoidable…
Average the polls–all of the polls–and don’t dismiss any of them just because they seem odd or you don’t like the results for your candidate. Right now, that would indicate that Clinton is probably up by 10-12 points. And so she probably is. However, as the differences between the varying polls shows, there is still a lot of movement left in this electorate. It ain’t over until February 6th.

In his previous post Bowers discussed some of the problems with the most recent polls, noting:

Could the difference be social pressure, where Democrats don’t tell live-interviewers that they are currently leaning against Clinton? Rasmussen’s numbers consistently back up that theory, but those produced by Harris do not. Could it be that traditional live-interview polls and newer polling methodologies sample different universes of voters, thus producing different results? Possibly, but even if that is the case, it is extremely difficult to say which group of polls is sampling a more representative universe right now, both because we don’t know who will vote in the 2008 primaries and because few polling firms release comprehensive crosstabs and methodologies. Could it simply be that when it comes to the 2008 Democratic nomination, live-interview polls are growing less useful due to the rising wireless-only population and social pressure, or that newer techniques are not yet able to achieve the same level of accuracy as traditional methods? Both are possible, but neither can be confirmed at this time.

The rapid increase in wireless only voters does present an interesting challenge to pollsters. Pollster.com‘s Mark Blumenthal sheds some fresh light on the problem here.