The state’s new chancellor’s “serious concerns” about whether one charter school should be allowed to operate didn’t stop her from supporting its second chance.

Chancellor Betty Rosa’s response to two charter schools, one with low student achievement and another that enrolls a few English Language Learners compared to the surrounding district, shows the fine line the chancellor must walk as she promotes high standards while also trying to give struggling schools the support they need. This time her convictions helped result in another chance for both schools, but her words left the door open for sanctions in the future.

“Montessori is a school that I have serious concerns about and that we will need to continue to monitor,” Rosa said.

Rosa discussed two schools: Harriet Tubman Charter School in the Bronx, which enrolls almost 18 percent fewer English Language Learners than its surrounding community school district, and New York City Montessori Charter School, which saw only 5 percent of student pass state English exams last year.

The chancellor only has one vote, but she is influential as the board’s leader. The board renewed both schools, though Harriet Tubman secured a full five-year renewal, while Montessori got the right to remain open only for another three years before its next review.

Rosa acknowledged and addressed each issue head-on. Harriet Tubman still needs to enroll more English language learners, she said, but she also complimented the school’s efforts to enroll more poor students. The school has increased its percentage of poor students by 15 percent in just one year, bringing it within seven points of the district average.

“Overall you see a charter school that has made a commitment,” Rosa said.

The chancellor’s tone towards the Montessori school was more cautionary. Rosa said she had “serious concerns” about the school, which unlike many charter schools prioritizes independent learning over sharp academic gains, and promised to continue to monitor its progress.

Her reaction to each issue is telling. Traditionally, charter schools have been judged primarily based on their test score performance, but increasingly schools have been under pressure to enroll more high-needs students, too.

With each school renewal on Monday there was also a practical concern: Are there other options for families? Regent Lester Young asked whether closing schools with only a few months’ notice is unfair to families. But he also argued the board should ensure that charters honor the bargain they made when they were authorized and keep their academic bar high.

“What I worry about is that here we are saying let’s give them a chance, let’s do this, when they got a chance, right?” Young said. “Their chance was they received a charter.”