October 21, 2008

Which Poll Should You Trust?

I'm a political junkie, and I've already written about the polling sites, Pollster and FiveThirtyEight, that I visit every day.

In a wonderful post, Tracking Poll Primer, Nate Silver at 538 explores the issue of why particular polls have "biases" toward one party or the other. Most often, the "bias" comes not from ideological leanings, but from assumptions that must be made -- most commonly, what demographic breakdowns should be assumed for the polls? If you read the post carefully, you'll have a little more understanding and sympathy for why polls taken on the same day(s) differ so much.