What goes into creating a political poll?

Friday, Kevin Nicholson looked around and was happy with what he saw.

He stopped to visit supporters in Chippewa County one day after a new NBC News/Marist poll showed the candidate for U.S. Senate led his Republican rival Leah Vukmir (38%-28%) as they approach next month’s primary.

"They all show good momentum. At this point, I think there have been 11 polls in the primary and I think we've been winning in like nine or 10 of them. So we're in a very good position here to win the primary,” Nicholson said. “I feel incredibly confident we're going to win August 14th and its allowed me keep my focus on (incumbent Democrat Sen.) Tammy Baldwin.”

That poll, however, is just one in an ever-growing list of rundowns from an already-long campaign season.

There's also the Marquette Law School poll. The most recent head-to-head numbers from June put Nicholson down 11 percent (50%-39) to Baldwin.

"These polls were taken two weeks ago. So, they were a snapshot that was accurate two weeks ago. Whether they are accurate today or not, who knows," John Frank, WEAU’s political analyst, said Monday.

As a Wisconsin voter, which poll – Marquette or NBC/Marist – is the one to follow?

"The methodological is very similar to the Marquette poll, where these are live caller polls that you end up having. Marist is based in New York state and not in Wisconsin, like Marquette is," Mark Murray, senior political editor with NBC News, said to WEAU 13 News on Monday.

The distance between Poughkeepsie, N.Y. (home to Marist University) and Milwaukee (site of Marquette) is roughly 900 miles, yet the polls seemed to show one race that was just as distant between them.

The Marquette poll in June showed incumbent Gov. Scott Walker with a four-point lead (48%-44%) over Democrat Tony Evers, while last week’s NBC News/Marist poll had Evers leading 54-41 over Walker.

“The Republicans were telling me that the race is much, much closer than the 13 to 14 points that our poll ended up showing,” Murray said. “To me, one poll here, one poll there, I think the biggest takeaway is Scott Walker is in a really, really tough race this cycle.”

Murray said one area which the polls were very similar was in the Democrat field – with Evers holding sizable leads over the remaining challengers within his party.

"When I see a poll that ends up showing 25% for someone like Evers at the very top and it's so crowded for everyone else, sometimes that person at the 25% ends up winning or sometimes the other candidate who's able to consolidate all that other vote ends up coming ahead,” he said. “So we got to see what actually plays out in the next couple of weeks in your state."

Charles Franklin, the director of the Marquette Law School Poll, said differences between polls are expected.

"We're talking to a sample to the population - not the whole population. So, of course, results are going to vary,” he said to WEAU 13 News on Monday. “That's why we have a margin of error of about four points, or for the primaries, about seven points in both the Marist and our polls. So, there are some differences there."

Franklin also said a poll’s margin of error is like counting how many times you call for a quarter to come up heads or tails.

"If you flipped a coin and you six heads in 10 flips, you wouldn't want to accuse the owner of the coin of using a biased coin against you, right? Six out of 10 times would happen pretty often – even seven out of 10 times would happen pretty often,” he said. “But, if you flip that coin a thousand times and it came up 600 or 700 heads, you'd have much stronger evidence that something was wrong with this coin, that it wasn't a fair coin. That's what's going on with the margin of error."

Along with the Marquette and NBC News/Marist polls, a third poll released Monday from Emerson College out of New York showed Evers leading 48%-41% over Walker.

“It's better to have several polls and average them than it is to treat any one poll as necessarily right. So if you did that with our polls and then you put in this Emerson poll as well, then the average of that is maybe Evers they had by three or maybe four points,” Franklin said. “That's a much closer to even balance in the polls than the 13-point margin that Marist has and it’s an alternative to the 4-point Walker lead that we’re showing.”

In the U.S. Senate GOP primary, the Emerson poll puts Vukmir and Nicholson in a near dead-heat (35.0%-34.6%).

Frank cites three areas to look at for a good poll – how questions are asked, who is asked the questions, and how well demographics of the sample polled match those of voters, in general.

“The Marquette poll matches up very well with short-term demographics of the state of Wisconsin. The Marist poll, less so,” he said. “It's not overwhelmingly bad, but it's got 8% more people taking the poll that are identified as Democrats and Republicans, and that certainly is not the short-term mix between Republicans and Democrats. It's not even the long-term mix between Republicans and Democrats. It's off by 2-6%.

"Both of them understand that this is a purple state and over 40% of our electorate is politically independent, ideologically moderate."

As for Nicholson, he says he's concentrating on just one poll.

"At the end of the day - and this is true - the only people that really matters is the one the voters take on Election Day," he said. “It is showing momentum and it's showing that our message is being received and that's good to know.

“You know what, you shouldn't spend any more than a couple seconds looking at a poll. It’s a good indicator and a snapshot in time, but at the end of the day, I need to keep doing what I'm doing here.