More accurate than Nate Silver or Markos—and simple, too

Earlier we learned that Markos predicted the results of the closest 2012 presidential races with more accuracy than Nate Silver at 538, who was the best of the polling aggregators and/or modelers.

But guess what—there's actually a free-range, locally produced, antibiotic-free, (relatively) simple model that, to my everlasting surprise, does better than both of them. It's based on the idea that most of the time, the polls are off by a fairly predictable amount related to the partisan lean of the state. I'll call it DRM (Dreaminonempty's Regression Model), 'cause I gotta call it something.

Returning to Markos' post, here's the table he posted with DRM predictions and polling averages for the final 10 days added in (the closest predictions for each state are highlighted):

And, to expand on the comparison, here's the Senate numbers (poll averages include entire month of October in some cases; see below the fold for details):
The average error of DRM predictions is lower for both close Senate and presidential races. Not only that, DRM predictions came closest to the actual result in 12 races, while Markos grabbed the honors in nine races, and the polling average was best three times. It looks like we can add another successful, reality-based, Daily-Kos-originated prediction model to the collection!

And the best news? It's easy to make a DRM prediction. See below the fold for simple instructions and analysis of additional races.