With voting about to begin in the presidential primaries, how much faith can we put in polls?

Presidential polls are our best way to gauge which candidate is in the lead. But, with less than a week to go before Iowa votes, their accuracy can change.

“They can be very accurate the closer you get to Election Day,” GOP consultant Patrick Davis said.

On the Democratic side, Hillary Clinton holds a national lead over Vermont Sen. Bernie Sanders.

However, in Iowa, it’s deadlocked.

Davis contends at this point, state polls matter most.

“If they win in Iowa, if they win in New Hampshire, they get a certain percentage of delegates,” Davis said “So, for us as observers we want to see how they’re going to do in these individual state races.”

Veteran Colorado College political science professor Bob Loevy argues voters can’t trust the polls when the numbers are too close-to-call.

“They’re only good for predicting landslide-type victories,” Loevy said. “When it’s close polls have great difficulty being accurate.”

Polling is far from an exact science. The results next Monday night in Iowa could be different than these past predictors.

“I’m always looking for a surprise result in Iowa, it’s produced a lot of them,” Loevy said.