By Emily Tillett CBS News August 20, 2018, 1:42 PM Voters need to "go past the horse race" in polls, CBS News' Anthony Salvanto says

Ahead of a closely watched midterm election, CBS News' Elections and Surveys director Anthony Salvanto says that voters and poll observers need to take a lesson from the 2016 presidential election and "go past the horse race" of polling data. In Salvanto's upcoming book, "Where did you get this number?" which explores common issues pollsters face, as well as a look back at Donald Trump's stunning victory, readers take an insider's tour of how the numbers played out in 2016.

"One of the things I wanted to get across in the book is — hold on a second, okay — let's go past the horse race, and let's look at what people are thinking and feeling — and it's August — that's the dynamic, that's the interesting part," Salvanto told "CBS This Morning" on Monday.

Salvanto denied that anything was wrong with the 2016 polling, after President Trump's stunning upset over Hillary Clinton, who ultimately secured the popular vote.

"All the signs were there," said Salvanto. "Republicans, at the same time, a little bit like right now, were talking to us in the polls but saying they weren't sure if they were going to back Trump. Were we really shocked that they came home? They were conservatives. Democrats were telling us they weren't enthusiastic, well, we should have understood then they might not show up, and in fact, they didn't."

He added, "So while it did surprise a lot of people, if you saw the whole picture — and I like to think that our viewers got a lot of that story — maybe you weren't as surprised."

Looking ahead to November, as CBS News' latest polling shows that Democrats have improved their standing in the fight for control of the House this midterm season by plus or minus 11 seats, Salvanto says pollsters continue to wrestle with the question of how to accurately count people who say they're not interested in voting.

"When somebody says that they're not interested, what would make them change and become interested? So we try to get at that," he said.

Salvanto cautioned that while Democrats are in a stronger position in 2018, there's a margin of error in that finding and "plausible scenarios in which Democrats gain seats but fall short of control."

"This year its not predetermined, and polls are not predictions, when people are telling you they are uncertain, believe them," he added.

"Where did you get this number: A pollster's guide to making sense of the world," published by Simon and Schuster, a division of CBS, will be released Tuesday.

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