WASHINGTON — For one day at least, the battle this year for Colorado’s U.S. Senate seat wasn’t about health care, the economy or immigration.
Instead, a debate swirled Thursday over terms one would more often associate with a college statistics class: sample size, poll average and margin of error.
The trigger for this fight was new polling from Quinnipiac University that showed Republican Cory Gardner ahead of Democratic incumbent Mark Udall by 8 percentage points — the largest lead to date for the challenger among publicly released polls, according to a slate of surveys compiled by the website Real Clear Politics.
In response to Gardner’s striking lead, partisans on both sides spent the day arguing about the methodology used in compiling the poll, as well as what it means for a race that could determine which party controls the U.S. Senate next year.
The polling debate is not without consequence. Morale among supporters can rise and fall with poll numbers. More importantly, the national parties — as well as wealthy political patrons — scrutinize polling data to determine where to spend money each election cycle.
For their part, Democrats dismissed the Quinnipiac poll as an outlier from other recent surveys, which have shown the two candidates either neck and neck or — in the case of a NBC News/Marist Poll from early September — with Udall in front by 6 percentage points.
To bolster that theory, Udall campaign manager Adam Dunstone took the unusual step of publicizing top-line, internal polling figures, which showed Udall ahead by single digits — although the campaign did not release the full poll results.
“It’s a tight race, was always going to be that way. Internals have been steady, no wild swings like you see in the news,” wrote Dunstone on Twitter.
A poll done earlier this month by SurveyUSA for The Denver Post put Udall ahead by 4 points, with a margin of error of 3.9 percentage points.
Republicans, meanwhile, jumped on the latest results as a sign that Udall was headed toward defeat.
Specifically, they referenced results in the Quinnipiac poll — and another released Wednesday by Suffolk University/USA Today — that suggest low approval ratings for President Barack Obama was hurting Senate Democrats such as Udall.
“Two days, two Colorado polls that spell trouble for Mark Udall,” wrote Michael Short, a spokesman for the Republican National Committee, in a statement.
According to the Quinnipiac poll, 33 percent of independent voters considered their vote in the Gardner-Udall contest as a “vote against Barack Obama.” To that point, 55 percent of those polled by Suffolk University/USA Today had an unfavorable opinion of Obama.
National dissatisfaction with the White House has led to some speculation that a Republican wave could be building across the country that would sweep the GOP into control of the U.S. Senate.
Another Quinnipiac poll this week, for example, put Joni Ernst, the Republican candidate for Iowa’s Senate seat, ahead of her Democratic opponent Bruce Braley by 6 percentage points; the margin is much different than what other polls have indicated, according to polls compiled by Real Clear Politics.
These results, coupled with Quinnipiac’s take on Colorado, suggest either the firm is picking up the early signs of a previously undetected surge for Republicans or that its recent data is an outlier from the rest of the polling universe.
An analysis on the fivethirtyeight.com website, said the results were interesting, but that readers “should be wary.”
On Thursday, Quinnipiac officials defended their findings.
“Do we think this is an aberration? No,” said Tim Malloy, assistant director of the Quinnipiac University Poll, when talking about Colorado. “Do we stick by the numbers? Yes.”
Specifically, its survey in Colorado found that likely voters favored Gardner 48 to 40 percent, with independent candidate Steve Shogan netting 8 percent. In its survey, Quinnipiac polled 1,211 likely Colorado voters Sept. 10-15; its listed margin of error was 2.8 percentage points.
Malloy said the voters’ attitudes toward Shogan “seemed to jump out in our research.”
Not only did the independent candidate reach 8 percent, but the former Democrat seemed to be sapping more voters from Gardner than Udall. Of the 8 percent of voters who said they supported Shogan, 52 to 42 percent said they would pick Gardner as a second choice — although 63 percent of Shogan supporters said they may change their mind before the election.
Reached by phone, Shogan found the results encouraging.
“Given the disadvantages” of competing against the two major parties, “we have done a pretty good job of getting our message out,” he said.
Political observers have raised doubts about the accuracy of Thursday’s Quinnipiac poll, citing a similar poll released by the group Wednesday — which was also strongly criticized — showing Gov. John Hickenlooper trailing his Republican opponent Bob Beauprez by 10 points.
Combined, experts say, the results could point to Quinnipiac having drawn from an unusual sample.
“This is an example of why you need to look at an amalgamation of polls and not any one poll,” said Eric Sondermann, an independent political consultant. “Polls have outliers, and this is an outlier.”
Added Steve Welchert, a Democratic political consultant: “You’ve got to be cautious about putting stock into polls that are this outside the mainstream.”
He said voter turnout this year remains a major question.
“This is the first time ever with mail-in ballots going to every (active) voter in Colorado,” Welchert said. “That is the one variable that a turnout model cannot even begin to gauge.”
Mark K. Matthews: 202-662-8907, mmatthews@denverpost.com or twitter.com/mkmatthews
