Friday, October 05, 2012

Exit Polls Have a Long Standing Democratic Bias

Exit polling has a long history of Democratic bias. Nate Silver, the NYT's poll guru, had a very good post up on the subject in 2008. He brought up some doozies:

1. Exit polling showed Bill Clinton winning Indiana and Texas(!?!).
2. Exit polling showed Gore winning Alabama and Georgia(!?!)

Succinctly stated:

"Exit polls have consistently overstated the Democratic share of the vote." 

Mark Blumenthal used to post at "MysteryPollster.com", and now is in charge of HuffPost's "Pollster.com". He characterized a study on exit polling this way:

"In short, Mitofsky and Lenski have reported Democratic overstatements to some degree in every election since 1990. "

The most recent example of this exit poll bias was in the Wisconsin recall election, where exit polls indicated a tight race:


"The numbers seemed to pop off the screen — 50 percent apiece for Barrett and Republican Gov. Scott Walker, the subject of the recall effort. Walker had a clear lead in independent pre-election polls, so the tie score sent analysts scrambling and buoyed Democratic hopes when the numbers were widely reported elsewhere minutes later at the official poll close time. 
Just a half hour later, the exit poll shifted to 52 to 48 percent, tilting in Walker’s favor."


but the actual result was a solid 7 point win by Walker, the Republican governor.