When the major networks called the recall election for Republican Scott Walker barely one hour after the polls closed at 8 p.m., there was widespread disbelief over the results - among Democrats, at least - and bewilderment over the process. Some of the confusion was understandable. The same networks just 30 minutes before had released early exit polling data showing the race between Walker and Democratic challenger Tom Barrett was a dead heat. People were also ticked off that the election was being called with just over 20% of wards reporting and voters still in line in Milwaukee waiting to cast ballots. It struck many in the heat of the moment that corporate media had usurped the democratic process.
One woman tweeted in disgust at 9 p.m.: "Ok NBC get a grip 22% and you're calling it? Puke."
Even the Associated Press seemed sensitive to the criticism, putting out an article that night with the headline "How the AP calls elections before all the votes are tallied."
The piece states that the AP never calls a race before polls close and bases its decision on a variety of factors, including "early vote returns provided by state and county elections offices, exit polls conducted with voters and vote results from a random sample of precincts around the state. It's a complicated process that also compares the voting history of counties to make sure results are in line with past trends."
AP said it made its call at 9:05 p.m. with 37% of precincts reporting and early returns showing Walker ahead 59% to 40%.
Georgia Duerst-Lahti, political science professor at Beloit College, says the tools used by media make it possible to predict results "with a relatively small sample size."
As to those exit polls, they're really just one poll. The news networks and AP hire Edison Research, which sends workers to key precincts to question voters as they exit the polls on how they voted and to collect voters' demographic data, including race, sex and gender.
Writing in The Atlantic on June 7, Molly Ball notes that the consortium gets raw data from Edison throughout the day. The information is supposed to be embargoed until the polls close but leaks inevitably happen and spread quickly on the Internet.
Ball says that early exit polls are often wrong because, among other things, they carry a margin of error, like any other survey; different people may be voting in the morning than in the evening; and some people may be more inclined to talk to a pollster. Dems seem to fall more often in the latter two groups, which could be why early exit polls often lean left.
In any case, they're not designed to call an election but provide an "incredibly rich trove of data for political analysts," says Ball.
Among the more tantalizing results of the Wisconsin exit polls: 51% said they'd vote for President Barack Obama and 44% for Republican challenger Mitt Romney if the election were held that day. And, despite Walker's successful move to eliminate collective bargaining rights for most public workers, 38% of those who live in union households voted for Walker and 62% for Barrett.