Texans got two very different snapshots last week of the Senate race between Republican incumbent Ted Cruz and his challenger, Democratic Congressman Beto O’Rourke.

Earlier in the week, a poll showed Cruz had gained a slightly wider lead in the race. The next day, however, the O’Rourke campaign announced it had raised a record-breaking $38 million in three months – more than three times the money Cruz’s campaign had raised in the same timeframe.

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All this money has translated into a lot of ads – and a lot of people knocking on doors. Texans could be getting a lot more visits from people working for the O’Rourke campaign, in particular. That’s because his team has a lot of money to spend and has set its sights on nonvoters.

KUT's Ashley Lopez reports

“Getting to people who typically don’t vote is really difficult,” says Brandon Rottinghaus, a political science professor at the University of Houston.

Rottinghaus says campaigns are notoriously bad at reaching nonvoters because it takes a lot of work. Studies show campaigns need to connect with a nonvoter – in one form or another – at least six to eight times before that person actually votes, he says.

“That’s a lot of interaction,” Rottinghaus says. “And it’s expensive to be able to not only do that, but also to do that in a way that you can re-create and continuously do.”

"Like so much of polling, it's a little bit of art and a little bit of science."

Unlike a lot of Democratic campaigns in Texas, O’Rourke's has the funding to do that work on a wide scale, which could add some unknowns to the race.

“I still think it’s a margin-of-error race,” says Albert Morales with Latino Decisions, a national Latino polling firm.

Morales says all this money and the excitement around the Senate race has made polling a little harder.

He says 1.6 million people have registered to vote in Texas since the last midterm election in 2014. By comparison, California, which is a bigger state, grew its voter rolls by 1.5 million in the same time period.

It’s hard to tell whether this increase is due to Texas' population growth, but Morales says his hunch is that it's because O’Rourke is reaching out to Texans who typically don’t get attention from campaigns.

“He’s just added, I think, a lot of new voters into the mix that are not going to be showing up in a lot of these polls that folks are doing,” he says.

Morales says it’s hard for pollsters to build out a model that predicts what the electorate is going to look like.

“None of these 1.6 million new voters are going to be showing up in any of the polling,” he says. “They are just not.”

Elections where voter turnout is expected to be high are also hard to poll. Rottinghaus says pollsters have to blend turnout models from different years to somehow try to predict what the electorate is going to look like.

“Like so much of polling, it’s a little bit of art and a little bit of science,” he says.

None of this is easy to do – and it creates other problems.

“That creates some uncertainty in a model,” he says. “Modeling people who don’t typically vote or a big surge [of voters] … could be a real problem and really difficult to figure out."

That doesn’t mean polls are wrong. Many political experts in Texas still think this is Ted Cruz’s race to lose.