by Patrick Appel
Nate Silver's guide to the GOP presidential nomination race:
[T]he area of each candidate’s circle is proportional to their perceived likelihood of winning the nomination, according to the Intrade betting market. Mitt Romney’s circle is drawn many times the size of the one for the relatively obscure talk-radio host Herman Cain because Intrade rates Mr. Romney many times as likely to be nominated. ... the color of each circle reflects the region the candidate is from: blue for the Northeast, red for the South, green for the Midwest, and yellow for the West.