Guess what? If you pay people more and treat them nicely, they’re more likely to keep working for you.

That’s the gist of a study by the Sunlight Foundation that tracked retention rates in Congressional offices during a two-year period.

The group, which said the study was the first of its kind, used data from the House Chief Administrative Officer to determine that the average retention rate from the third quarter of 2009 to the third quarter of 2011 was 64.2 percent.

Spokesmen for Members of Congress whose offices ranked low for staff turnover say it always helps to have a great boss; those in offices that were ranked on the opposite end of the spectrum argued with methodology.

Lee Drutman, a senior fellow at the Sunlight Foundation, also found that offices with high retention rates tend to pay their staffers higher salaries.

Rep. Betty Sutton (D-Ohio) was listed as having the lowest retention rate in the House — 19.2 percent.

In response to the news, she issued a statement to Roll Call to say she was “thankful for the hard work each of my staff members does on a daily basis for the people of the district.”

Rep. Mike Capuano (D-Mass.) had the highest number of staffers stick around during that period: His office’s retention rate was 93.8 percent, with only one staffer leaving in a two-year window.

“It’s pretty simple: Mike’s a great boss,” spokeswoman Alison Mills said. “He is always open to our ideas and willing to hear us out, no matter what the issue is — and we appreciate that.”

Representatives for offices that ranked near the top with Capuano echoed the sentiment.

“An emphasis on teamwork and a positive atmosphere make our office an excellent place to work,” said Meghan Snyder, press secretary for Rep. Jim Jordan (R-Ohio), whose office had the fourth-best retention rate.

Derek Harley, chief of staff for Rep. Wally Herger (R-Calif.), whose office had the third-best retention rate, attributed low staff turnover to the office’s philosophy of promoting from within.

Spokesmen for offices ranking low on the staff-retention scale said the report, released Monday, did not take multiple variables into account, a point that Drutman acknowledged.

Doug Sachtleben, a spokesman for Rep. John Fleming, noted that the Louisiana Republican had to assemble his team quickly after his election was postponed because of Hurricane Gustav and that some staff left because of illness or motherhood. Fleming had the second-lowest retention rate in the study.

Sarah Rozier, press secretary for Rep. Jeb Hensarling (R-Texas), whose personal office was 14th from the bottom, pointed out a methodological flaw: “The report is not accurate because it fails to account for staff members who left Congressman Hensarling’s personal office to work for him in his capacity as [House Republican] Conference chairman.”

Drutman said he had used only data from Hensarling’s personal office and emphasized that it was important to recognize the idiosyncrasies inherent in findings such as these.

“Certainly every office is different, and there’s no reason to say that somebody must be a terrible boss, but what we’re looking at is aggregate patterns across all offices,” Drutman said.