The science, shortcomings of political polls

Vote. (FILE)

As more political polls come out ahead of Election Day, many voters question their accuracy.

To get some clarity, Fox Illinois reached out to polling expert and University of Illinois Professor Brian Gaines.

Gaines explained it’s all about finding a random sample of voters — something that’s become increasingly difficult in the 21st Century.

“We get a lot of people on the phone over 50,” Gaines said. “We can’t seem to get people on the phone under 30, so we use the internet to get the people under 30 and we mix the two together.”

He said one of the biggest challenges can be polling the type of voter who doesn’t want to be polled.

"It shows up in both worlds,” Gaines said. “It shows up in the telephone world, people just won't answer your phone call. And it shows up in the internet world because they're never going to end up in the [online] panel in the first place."

Although some voters look to several polls for accuracy, Gaines said that probably doesn't do much.

"If there's a problem with the polls, it's often going to be true with all of them,” he said. “If they're all systematically underestimating, say the number of voters who will be without a college education, then having five, 10 or 50 polls won't matter. They'll all have the same bias.”

According to Gaines, another common factor throwing polls is when people say they'll vote one way, but vote another come Election Day.

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