Are liberals more accurate predictors of events than conservatives?

"Partisanship had a significant role in a prognosticator’s overall accuracy. Our scale measured it from 1 (most conservative) to 9 (most liberal,) and as partisanship “went up” one level (a person was rated more liberal) there was a moderate increase in their predictive capacity...Democrats seem to be better at predicting than Republicans, but we are cautious in claiming that this is a generalizable conclusion outside of our time period. There may be underlying factors in the 2008 elections that might not occur in other time periods. It’s also plausible that partisan strategies may lead to inaccurate predictions by Republicans--Republicans, unlike Democrats, may hope to face who they see as the weaker candidate from the opposing party in November. This may mean that some predictions are not really meant to be predictive--rather, they hope to shape the debate. Of course, it is certainly possible that Democrats really are better predictors." — Are Talking Heads Blowing Hot Air?An Analysis of the Accuracy of Forecasts in the Political Media

In others words: Republicans are either a) whistling to keep their spirits up, b) are in possession of a genuinely less empirical world view, or c) some mixture of the two. The results:—

Paul Krugman 8.23

Maureen Dowd 7.27

Carl Levin 7.2

Ed Rendell 7.0

Chuck Shumer 6.92

Nancy Pelosi 6.3

David Brooks 5.55

Eugene Robinson 5.45

Mick Huckabee 3.36

John Kerry 2.5

Newt Gingrich 2.5

Bob Herbert 2.22

Thomas Friedman 2.0

Hillary Clinton 0.0

George Will -0.04

Joe Lieberman -1.1

Lindsay Graham -3.26