Frustrated by illogical poll analysis, baseball statistician Nate Silver started modeling data on his Web site, FiveThirtyEight.com. He spoke to Adam B. Kushner last week.
How do you design your model?
A lot is based on intuition. We look at how a pollster has done in the past, whether a state leans left or right, who lives there, how things usually change leading up to the election. There's no one principle, except to be meticulous and thoughtful.
Which polls are reliable?
Good ones are boutique firms like SurveyUSA or Rasmussen Reports. Gallup doesn't have a good record. Zogby has a poor record. You have trouble reaching younger voters because they have cell phones … if you're not careful, you'll radically undercount younger votes.
You prefer Obama. Is there a conflict of interest here?
There's separation between my analysis and the model. I may not like a poll, but I still have rules about which polls to weigh.
Where do you go from here?
We'll look at Congress to predict who votes for which bills. It would be good to look up a senator's stats like the way you do in baseball.