Is Ted Cruz or Beto O'Rourke leading Senate race? How to make sense of political polls

By Andy Cerota - Anchor/Reporter

HOUSTON - In the race between U.S. Sen. Ted Cruz and his challenger, Rep. Beto O’Rourke, who’s got the advantage?

The answer could depend on which poll you believe.

The Qunnipiac Poll, which came out Tuesday and shows Cruz with a comfortable lead over his opponent, surveyed likely voters by phone. The Ispos Poll, released Wednesday and shows O’ Rourke with a narrow lead, was done online.

“You've got a different mix of partisanship, you've got a different style of accumulating a sample, you've got a different mix of likely voters; depending on the parts of the recipe you put together, you're going to get a different outcome,” said Brandon Rottinghaus, University of Houston political science professor.

Rottinghaus said online polls reflect what you put into them and tend to skew toward a younger, more liberal sample.

“So it's not surprising. Maybe you see O'Rourke doing slightly better on an online poll than a ... landline poll,” Rottinghaus said.

Rottinghaus said a poll is simply a snapshot and warns against putting too much stock in one survey since no one poll can tell us as much we’d like.

“If I had to pick one or the other, I'd pick the Quinnipiac poll. That said, I do think that it doesn’t reflect the enthusiasm that is occurring,” Rottinghaus said.

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