Wednesday, March 05, 2008
Following the numbers in the presidential race
While you're visiting the Progressive Review website, hidden among all the articles is some excellent mathematical analysis of poll results.
Sam Smith uses a rolling average method that he has tested out over time.
His web page, Smackdown 2008, is located here. It may be confusing at first, but enlightenment comes if you study the color codes.
Sam describes the method in this article. Snippet:
Once again, the Progressive Review's Morning Line Rolling Average - exclusive until a number of the bigger outfits copied it - has proved its worth. Based on 31 polls this season, the Morning Line had an average error of 6 matched only by Survey USA.
Typically, our rolling average involves the last three polls in a race, although sometimes we adjust it when there are only a few, or if there are many, polls in the final days. By smoothing out the poll results, we limit the flaws in any individual polls.