Many Boston charter schools that have opened additional campuses frequently scored higher than state averages on last spring’s MCAS, a sign that high performance can be sustained as more students enroll, according to a Globe review of data released Friday.
In one of the strongest showings, the two new campuses of the Brooke Charter School network outscored the state at every grade level tested in English, math, and science, sometimes by more than 20 or 30 points.
Similarly, students at the Excel Academy Charter School network’s year-old campus in East Boston exceeded state averages in all subjects, much like its students at its original school, which is also located in East Boston.
Charter school leaders chalked up the results to top-notch teaching, high expectations, and other measures, such as strict discipline or intensive tutoring.
Jon Clark, co-director at Brooke Charter School, said his schools place a high premium on teaching.
“We revere teaching,” Clark said. “It’s the hardest job in the world.”
This year’s MCAS results provide the most extensive examination of the state’s effort to expand charter schools since a 2010 state law allowed for the doubling of charter school seats in districts with the lowest MCAS scores, such as Boston.
Currently, six of the new campuses have grade levels that must take part in the Massachusetts Comprehensive Assessment System, which tests students in grades 3-8 and grade 10. In many cases, the schools have results for only one or two grade levels because they start their schools small, opening with one or two grades and then adding others as students move up.
Overall, each of the six new charter schools in Boston exceeded state averages on at least one section of the test, and almost always scored higher than the average for the Boston school system.
Other schools that opened additional schools are Match, which launched Match Community Day, and Roxbury Prep, which opened two campuses.
KIPP, a national charter chain, also opened its first school in Boston.
Created originally under the 1993 Education Reform Act, charter schools were envisioned to be laboratories of educational innovations and were expected to be a boon for families seeking alternatives to traditional school systems, particularly low-performing ones. In most cases, charter schools are run independently of local school districts and rarely employ unionized teachers, providing flexibility to make quick changes.
Boston currently has more than 20 charter schools and the city has once again hit the limit on the number that can operate — prompting charter school advocates to push for raising the cap again, a hot issue in this year’s mayoral race.
Richard Stutman, president of the Boston Teachers Union, which opposes more charter schools, downplayed the results of the charter schools, arguing they serve a different population of students than Boston’s school system. He also accused charter schools of pushing out academically weak students before the MCAS exams are taken each spring — an assertion charter leaders have long disputed.
“Charter schools don’t educate nearly their share of English language learners or special education students so their scores don’t mean much,” Stutman said. “I will commend them for doing well but their results are skewed by their demographics and teaching philosophy — teaching to the test.”
While charter schools have been immensely popular among low-income, black, or Latino students, most charters have enrolled small rates of students with disabilities or those lacking English fluency. The 2010 expansion law has forced charter schools to step up recruitment of these students, with mixed results.
One charter school in particular has responded aggressively. Two years ago, Match Community Day Charter Public School in Jamaica Plain opened specifically to serve high concentrations of students lacking fluency in English, and 86 percent of its enrollment is comprised of these students.
This past spring, 90 percent of the school’s third graders — the first to take the MCAS — scored proficient or higher, 24 percentage points higher than the state average. The students performed well in reading too, with 53 percent scoring proficient or higher. While that’s four percentage points lower than the state average, it’s more than 20 percentage points higher than the Boston School Department’s average for third graders.
“We are immensely gratified,” said Kate Carpenter Bernier, the school’s principal. “It took a lot of work, on our part, our scholars’ part, and the part of our families.”James Vaznis can be reached at firstname.lastname@example.org. Follow him on Twitter @globevaznis.