Along with Public Policy Polling, Rasmussen Reports was the most active polling firm in Illinois this cycle. Throughout the summer and fall, their research consistently gave GOP gubernatorial nominee Bill Brady a sizable lead in Illinois' gubernatorial race; in the last eight polls the firm conducted, Brady averaged a 7.8 point advantage.

It seems now that those figures were wildly inaccurate. While a strong progressive ground game gave Gov. Pat Quinn a huge edge on Election Day, it's also probably true that Quinn himself never trailed as badly as some assumed.

What explains Rasmussen's poor performance? For whatever reason, the firm refused to include all of the candidates in their surveys and thus missed the number of potential Brady voters who decided instead to support Scott Lee Cohen. But FiveThirtyEight's Nate Silver says the problem with the firm's tactics, which rely too heavily on "party identification," runs deeper:

We have critiqued the firm for its cavalier attitude toward polling convention. Rasmussen, for instance, generally conducts all of its interviews during a single, 4-hour window; speaks with the first person it reaches on the phone rather than using a random selection process; does not call cellphones; does not call back respondents whom it misses initially; and uses a computer script rather than live interviewers to conduct its surveys. These are cost-saving measures which contribute to very low response rates and may lead to biased samples.

These results are worth keeping in mind next election cycle.