For 10 years, MN Community Measurement has been putting heat on medical clinics by publicly ranking them on patient care — starting with performance measures on diabetes and vascular disease and now expanding into C-section rates and knee replacements.

Progress in that decade is beyond question. The share of diabetics at these clinics whom achieved optimal health has increased from 17 percent in 2008 to 38 percent last year, according to the 2014 health care quality report the organization released last week.

But after all this time, nobody really knows whether public measurement itself is responsible for the good news.

Doctors might be extra motivated because they don’t want their clinics to look bad to patients and peers. But it’s also possible that MN Community Measurement is simply a mirror reflecting progress at a pivotal time in our nation’s health care.

A study published this month in the Journal of the American Medical Association questioned whether publicized outcome data has any impact. Comparing surgical outcomes among U.S. hospitals that publicly reported their mortality and morbidity data, versus those that didn’t, researchers found comparable levels of progress in both groups.

Community Measurement’s executive director, Jim Chase, is confident that public measurement plays a key role — maybe like the gas that is needed in a car before someone can drive it.

“It’s hard to prove how much of it is due to just the measurement,” he said.

What has become clear in 10 years is that clinics have worked hard to make change happen, he said. Little tweaks to practices don’t cut it.

“You’ve got to do things differently,” he said. “It’s not by accident or just coming to work 10 minutes earlier.”

That’s why overall progress might be incremental — colorectal cancer screening rates at Minnesota clinics nudged up from 69 percent in 2013 to 70 percent last year — but is actually because some clinics made very large jumps.

Waconia-based Lakeview Clinic, for example, jumped 26 percentage points in its share of adolescent patients who receive their recommended vaccinations. Park Nicollet’s clinic in Rogers increased its share of diabetic patients at optimal health by 29 percentage points.

“Sometimes [the effort] pays off,” Chase said, “and you get a big change.”