Monday, October 27, 2008

Pollin'

I was reading the three political polling sites that I look at, last night -- fivethirtyeight, electoral-vote, and presidential electoral forecasts -- when my wife came into the bedroom and asked me if I was seeing anything interesting. I told her that the general trend was consistant, but one thing that really surprised me was that whenever electoral-vote zigged, PEF zagged. In fact -- I brought up the graph and deleted the 538 line, just to be able to see the other two more clearlu -- it was exactly that -- like one was forecasting Obama, the other McCain. I brought up the Methodology section of PEF, and I read this:

This web site presents predictions of the 2008 presidential electoral college outcome (if elections were held today) based on state level polls collected by electoral-vote.com. At least once a day, a script fetches those site's polls table, computes simulations of election outcomes (details below) based on state-level polls and posts them on the front page.

Oh. So one of the three sites that I look at is using base numbers from another of the three. I guess that explains why they're tied so closely together. So much for getting differing views of the same race. But - why inverted? And that, I still don't know.

No comments: