In a move blasted by charter school advocates, the Massachusetts Board of Elementary and Secondary Education refused Tuesday to abandon a new way of determining which districts get more charter schools and even voted to bolster the use of a controversial set of data.
The decision ultimately means that efforts to double charter school enrollment in cities such as Worcester and Somerville will grind to a halt because they no longer rank in the bottom 10 percent in the state. Under state law, only districts in the bottom 10 percent are eligible for a doubling of charter-school enrollment.
“It is a very disappointing decision by the board that will have a real negative impact on school choice on thousands of students,” said Marc Kenen, executive director of the Massachusetts Charter Public School Association.
Since 2010 when a change in state law allowed for the doubling of charter school enrollment, state education officials have relied on MCAS scores in determining the bottom 10 percent of districts.
But in March, the state board decided to give districts credit for how much they boost students’ test scores, in recognition that some districts with low scores may actually be increasing them at fast rates, a potential indicator of sound academic programs.
That change elevated districts such as Worcester and Somerville out of the bottom 10 percent, while moving a few districts with smaller percentages of low-income students, like Easthampton, into that category.
Then on Tuesday the state board voted unanimously to bolster the weight of these so-called student growth scores so it makes up 25 percent of the formula, instead of 20 percent. That pushed Lowell out of the bottom 10 percent.
The vote followed more than two months of lobbying by supporters and opponents of charter schools, each pushing their own proposals. Charter school supporters wanted student growth eliminated from the formula, while advocates pushed for stronger use of it.
The public furor caused the board to scrap a vote originally scheduled in April that would have increased the weight of student growth to 30 percent. Finally, last week, Mitchell Chester, the state commissioner of elementary and secondary education, settled on recommending 25 percent.
“This change reinforces our message that student growth is a valid metric and gives recognition to schools that are promoting strong year-to-year student learning gains,” Chester wrote in a memorandum outlining his recommendation.
“I am not recommending a larger increase in the weighting of growth, because it would start to distort the identification of the schools and districts that are most in need of our attention and assistance.”
But some charter school critics fault the compromise as weak.
“I don’t think they are paying growth enough attention and are doing a disservice to schools doing hard work,” said Richard Stutman, president of the Boston Teachers Union. “I think a fair formula would be a fifty-fifty split.”
That change would knock Boston out of the bottom 10 percent.James Vaznis can be reached at email@example.com. Follow him on Twitter @globevaznis.