Report: Metric that influences charter expansion is flawed

BOSTON -- Days after a compromise charter school expansion plan in New Bedford collapsed amid legislative delays, a new Pioneer Institute report is raising concerns with the method used to decide which school districts are eligible for an increase in the charter school cap.

The report, from Pioneer senior fellow Cara Stillings Candal, focuses on a metric known as the student growth percentile, one measure used, along with MCAS scores, in determining which school districts are ranked in the bottom 10 percent and therefore are eligible for a higher cap in charter tuition payments.

"It can give us some valuable information, but that information isn't necessarily super reliable," Candal said of the student growth percentile, or SGP, which accounts for 25 percent of district rankings.

In larger districts with more students, Candal said, the SGP is likely to cluster around a statistical mean, though individual students score higher or lower than that mean. Smaller districts do not usually tend toward the mean, she said.

"What we see is the small districts, where proficiency might actually be a little higher than the large districts, they're bumping into the bottom 10 percent," Candal said

Meanwhile, she said, "these really large districts, which also happen to be the districts where most parents want charter schools, like your Lawrences and your Bostons, they fall out of the bottom 10 percent."

Candal recommended state education officials move away from using SGP for charter cap increase purposes, and return to using just MCAS scores, which she said are "not a perfect measure, but much more reliable."

"Obviously Pioneer is a pro-charter school organization, and I'm a pro-charter school person, but I think that the more important thing here is less about 'Let's meet demand,' and it's more about, this is not a good statistical measure that we should be using for a high-stakes policy decision, because it's not necessarily a good reflection of what's happening in our school districts," said Candal, who chairs the City on a Hill Charter Public Schools Board of Trustees.

Massachusetts voters in 2016 rejected a ballot question that would have raised the cap on charter enrollment.

Last week, Education Commissioner Jeff Riley called off a deal between New Bedford officials and the Alma Del Mar Charter School, under which Alma Del Mar would have expanded to a new 450-seat campus at a former city elementary school and enrolled students from a neighborhood zone.

Lawmakers delayed consideration of the bill needed to facilitate the deal, which Riley wanted to see pass in May. Alma Del Mar will now open a 594-seat school, enrolling via a citywide lottery.

The Washington, D.C.-based Center for Education Reform issued a statement Tuesday evening reacting to the New Bedford situation, which Jeanne Allen, the center's founder and CEO, said she and her colleagues around the country had "watched with great interest."

"The irony should be lost on no one - critics argue charters should admit everyone in an attendance zone rather than by lottery but scuttled a plan to do just that. It shows you that their arguments are simply red herrings, and not honest concerns," Allen said.

Critics of the New Bedford plan objected to the idea of transferring what's now city property to a charter operator, and raised concerns about the drawing of the enrollment zone. They also called for more community involvement and a broader legislative debate about any changes to charter policy that are pursued.

"This was an attempted end run around the will of voters, who in 2016 rejected charter school expansions," Massachusetts Teachers Association President Merrie Najimy said in a statement Friday night.