Presidential Polling

I was hoping to include a link to a Real Clear Politics article talking about all the volatility represented in the different polls and why that's the case, but it seems that the permalink isn't working anymore and I have no way of digging it up again. It provided a great explanation about how all of the polls can have such varied discrepencies, but still purport to have 95% confidence that their numbers are correct.

In part it represents the volatility of the electorate, but at the same time it is also representative of the approach that each pollster uses in trying to decipher the composition of the American electorate.

On their website they list a number of different polls, with their margins of error, and then average those numbers out across them all. For example, the Pew poll showed 53% for Obama, 38% for McCain, with a margin of error of 3.5%. What that means is that they are 95% confident that the real averages of the population are within 3.5% of those numbers. So McCain's real average is somewhere between 34.5%-41.5%, but the RCP average for all polls shows that McCain has 44% of the support of the American people, well outside of the confidence range that the Pew poll suggests.

What it really means is that no one is really sure what the American public is going to look like come November 4th, if Democrats make up 40, 50, or 60% of the people in this country with a political party affiliation, and then what percentage of those people will actually come out to vote. Each poll has their own suspicions of what those numbers will be, and then based on those assumptions, get a stratified random sample to get a representative group to make predictions about the population as a whole.

So whatever the polls may suggest, we really don't know until the outcome is here. That's part of the reason why exit polls in 2004 had Kerry way out in front, but were way off in the actual outcome of the election. Take heart. Any one of these races are still up for grabs.

You know, that's actually a pretty damn good summary of what was in that article.