Students in most Minnesota charter schools are failing to hit learning targets and are not achieving adequate academic growth, according to a Star Tribune analysis of school performance data.

The analysis of 128 of the state's 157 charter schools show that the gulf between the academic success of its white and minority students widened at nearly two-thirds of those schools last year. Slightly more than half of charter schools students were proficient in reading, dramatically worse than traditional public schools, where 72 percent were proficient.

Between 2011 and 2014, 20 charter schools failed every year to meet the state's expectations for academic growth each year, signaling that some of Minnesota's most vulnerable students had stagnated academically.

A top official with the Minnesota Department of Education says she is troubled by the data, which runs counter to "the public narrative" that charter schools are generally superior to public schools.

"We hear, as we should, about the highfliers and the schools that are beating the odds, but I think we need to pay even more attention to the schools that are persistently failing to meet expectations," said Charlene Briner, the Minnesota Department of Education's chief of staff. Charter school advocates strongly defend their performance. They say the vast majority of schools that aren't showing enough improvement serve at-risk populations, students who are poor, homeless, with limited English proficiency, or are in danger of dropping out.

"Our students, they're coming from different environments, both home and school, where they've never had the chance to be successful," said April Harrison, executive director of LoveWorks Academy, a Minneapolis charter school that has the state's lowest rating. "No one has ever taken the time to say, 'What's going on with you? How can I help you?' That's what we do."

Minnesota is the birthplace of the charter school movement and a handful of schools have received national acclaim for their accomplishments, particularly when it comes to making strong academic gains with low-income students of color. But the new information is fueling critics who say the charter school experiment has failed to deliver on teaching innovation.

"Schools promised they were going to help turn around things for these very challenging student populations," said Kyle Serrette, director of education for the New York City-based Center for Popular Democracy. "Now, here we are 20 years later and they're realizing that they have the same troubles of public schools systems."

More than half of schools analyzed from 2011 to 2014 were also failing to meet the department's expectations for academic growth, the gains made from year to year in reading and math.

Of the 20 schools that failed to meet the state goals for improvement every year, Pillsbury United Communities is the authorizer for six of those schools: Dugsi Academy, LoveWorks Academy for Visual and Performing Arts, Connections Academy, Learning for Leadership Charter School, and the Minnesota Transitions Charter School's elementary, Connections Academy and Virtual High School. Those schools also missed annual achievement gap targets.

Officials with the Urban Institute for Service and Learning, which oversees Pillsbury's charters, say most of their schools cater to students at risk of dropping out, those who have been kicked out of other schools, and many who are learning to speak English.

"We intentionally work with students that most other people would really not want to work with," said Antonio Cardona, director of the institute.

Two years ago, Pillsbury closed Quest Academy, a small St. Louis Park charter school that consistently failed to meet state performance goals.

Cardona said Pillsbury would consider closing more chronically low-performing schools, or more likely, adopt new turnaround strategies. They also want to add some high-performing schools to their portfolio so that some of their low-performing schools might be able to absorb successful teaching strategies.

At LoveWorks Academy in Minneapolis, about 85 percent of the school's students qualify for free and reduced-price lunches. About 13 percent of its students were proficient in math and 12 percent are proficient in reading.

"What success means for me is our students are reaching the top," Harrison said. "We are going to work until we get there."

Some charter schools struggle with stability and finding qualified teachers who are the right fit. In one year, about 65 percent of LoveWorks' teaching staff turned over. Some left on their own accord while others were not offered their job back.

"I think that's why we're seeing success now because we have a staff that's willing to listen and learn and take the coaching," said Jamar Smith, the school's arts coordinator.

Just like traditional public schools, the highest-performing charter schools tend to serve students from more affluent families, the analysis shows.

There are some notable exceptions, many of which are noted annually in the Star Tribune's "Beating the Odds" list, which is a ranking of high-performing schools that serve a large number of poor students. For years, that list has been dominated by charter schools.

"These are schools that have fully utilized the charter school model to do what needs to be done," Sweeney said. "If a program isn't working, if a schedule needs to be changed, they have the flexibility to turn on a dime."

New Millennium Academy, a Minneapolis charter school that serves mostly Hmong students, has hit the state's benchmarks for improvement every year from 2011 to 2014. In 2013, it was designated a Celebration school, one of the state's top school designations.

Amy Erickson, the school's director of teaching and learning, said the school's improvement is due to a focused effort to help its students who are learning to speak English — about 85 percent of New Millennium's enrollment.

Among the ways the school has done that is through data-driven instruction. New Millennium tests its students about every six weeks to see how they're doing. Those who need extra help receive it in small groups.

"Many of our parents don't read or write English," said Yee Yang, the school's executive director. "So we have meetings where we just talk about the importance of education. We want to make sure they're focused on that, too."

In recent years, Minnesota has increased its scrutiny of charter schools, particularly organizations that authorize them. Starting in 2015, the state will begin evaluating authorizers. An unsatisfactory rating means an authorizer would lose the ability to create new schools.

The legislative effort has revealed a rift between differing charter groups.

Charter School Partners is supporting legislation that would make it easier for authorizers to close schools that perform poorly.

"We think it's an inoculation for our charter community," said Brian Sweeney, Charter School Partners' director of public affairs.

The Minnesota Association of Charter Schools, which represents about half the state's charter schools, will oppose any legislative efforts that give authorizers more authority to close low-performing schools.

"It's the teachers and principals who have a much more direct impact on student achievement," said Eugene Piccolo, the association's director. "Not the authorizers."

Instead, the association is throwing its efforts behind legislative proposals it believes might help level the financial playing field between charters and traditional public schools.

A recent report commissioned by Charter School Partners shows that Minneapolis Public Schools receives about 31 percent more in funding per pupil than the average Minneapolis charter school. St. Paul Public Schools receives about 24 percent more per pupil.

Charter school supporters say the model continues to evolve.

"Twenty years ago when charters began in Minnesota, it was 1,000 flowers blooming. Let's experiment. Let's innovate. Let's see what works" Sweeney said. "Nobody ever thought it was to have schools last forever that are failing. So there's a national move to improve the sector and I think we need to do that here in Minnesota."

Kim McGuire • 612-673-4469