A new county-by-county study of voter access in 17 swing states ranks Polk, Pine and Nobles counties as Minnesota's worst on Election Day 2012. The analysis prompted some spirited beyond-the-numbers explanations from county officials.

The study, just released from the nonpartisan American Progress Action Fund, analyzes 2012 voter turnout, registration, rejected absentee ballots and voters purged from the rolls in Minnesota's most populated 57 counties. Smaller counties were excluded as so-called data outliers that would skew the statistics.

"Our report highlights statistical anomalies that stand out from the crowd so people can start asking, 'Why were we different from the state average and what can we do better to improve our numbers?' " said Joshua Field, a co-author and deputy director of the Washington-based group.

The study lauds Minnesota for its same-day voter registration. The state joined Wisconsin, Colorado, New Hampshire and Iowa among the top five in voter turnout based on U.S. Census numbers of citizens of voting age. Each state boasted above 68 percent turnout, while Arizona finished the worst at 51.9 percent.

But the report took to task Polk County in northwestern Minnesota, Pine County north of the Twin Cities and Nobles County in the state's southwestern corner. All three counties finished in the bottom of turnout and registration rates among citizens 18 and older. But county officials point to the rate of registered voters who showed up at the polls and questioned why the study used census data when crunching its numbers.

I think it's very misleading, and I was very surprised," said Cathy Clemmer, the auditor-treasurer in Pine County, which ranked worst in turnout (61.6 percent) and registration (72.3 percent). "I'm not pleased with it. Talk to anybody in Pine County involved with elections in any fashion and they would be disheartened."

She said one explanation for her county's lousy showing is the federal prison in Sandstone, where roughly 1,250 inmates are counted in the census, but barred from ­voting as felons.

The study reported Minnesota had the highest rate of rejected absentee ballots at 2.8 percent compared to the national average of 1 percent. But Clemmer said when voters failed to sign absentee ballots, they were sent another ballot and those that were returned weren't counted in the study.

Clemmer pointed to Pine County's percentage of registered voters who turned out in 2012, a robust 91.2 percent.

"Granted, there are some people who don't care, but the folks who actually care about voting turn out in droves," she said. "Rather than just looking at the statistical numbers, they should have conversations with folks like myself."

Field, the coauthor, agreed. He said researchers evaluated nearly 10,000 localities in the study, which can be found at tinyurl.com/lajnjrl.

"We didn't intend to explain why," he said. "We're leaving that in the hands of the people on the ground."

Beth Van Hove, the new Nobles County auditor-treasurer in Worthington, said 80 percent of registered voters turned out in 2012. But the study said only 63 percent of Nobles County's voting-age citizens cast ballots.

"We have a large pork producing plant here and that transient population may play a factor with all the coming and going," Van Hove said.

She said all counties struggle to get all their eligible voters registered. In Polk County, which ranked worst when all access factors were weighed, Auditor-Treasurer Michelle Cote said she would be more concerned if all 87 counties were included instead of 57.

"That skews things right away," she said from Crookston. "If it were all-encompassing, I would be more alarmed."

Enhancements to her county's voting website and an increase in precincts choosing to use mail ballots should help. Currently, about one-third of Polk County's 87 precincts have opted to go with mail ballots and at least two more have decide to switch.

"I like mail ballots because voters are more likely to complete them in the comfort of their own home," Cote said.

Curt Brown • 612-673-4767