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.
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
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.