More than 700 students could be scrambling to find a new school for the next academic year after a D.C. board voted unanimously to revoke the charter of the city's only all-girls public school.

The six-member D.C. Public Charter School Board said Thursday that students at Excel Academy Public Charter School in Southeast Washington are lagging behind their peers, and the school — with students in preschool through eighth grade — shows scant evidence of improvement.

"The longer girls are at Excel, the further they fall behind their peers in the city," said Saba Bireda, a member of the charter school board.

While a drastic move, the revocation of a charter is far from unprecedented. The District has shuttered nearly two dozen small and large charter schools since 2012, although some have been able to remain open with new leadership.

The decision comes as enrollment in charter schools is burgeoning in the District, accounting for more than four of every 10 public school students. Other charter schools with large enrollments have faced a fate similar to Excel's; in 2014, at least three big charter schools were closed or taken over because of poor performance.

Each year, about 400 charter schools open in the country, while 200 to 300 close because of low enrollment, poor performance and financial woes, according to Todd Ziebarth, senior vice president at the National Alliance for Public Charter Schools, an advocacy organization.

"The bargain is that we are going to give these schools more room to innovate, but in exchange we are going to hold them to higher accountability," Ziebarth said. "When we see the D.C. Public Charter School Board doing this, it is upholding that bargain."

Excel leaders said they oppose the decision and are exploring options to challenge it, including a takeover.

"The narrative that we haven't been paying attention, or that we haven't attempted to make a change, is just wrong," said Beth Heider, chairwoman of the school's Board of Trustees. "We'll see what happens. We're not dead yet."

The D.C. Charter School Board said enrollment specialists would meet with each family at Excel to ensure they find a new school.

Under District law, the school board must review a school's charter to operate every five years to ensure it meets goals agreed to when receiving its charter.

Excel Academy was founded 10 years ago, and its students, who largely come from low-income families, have struggled to match citywide averages on math and English standardized tests. In the 2016-2017 school year, 9 percent of Excel students met or exceeded expectations in math, compared with 27 percent citywide. In English, 19 percent met or exceeded expectations, compared with 31 percent citywide.

Excel's operating charter stipulates it must score 45 percent on the D.C. Charter School Board's annual assessment of school performance, which takes into account attendance, test scores, re-enrollment rates and more. But over the past five years, the school has averaged just 41 percent.

The school board said its staff members had met with Excel leaders during the past two years to prepare for the five-year review, but the school has not reached all of its targets.

"This is not a decision that anyone on this board takes lightly," board member Rick Cruz said. "Our goal is to ensure that people who attend public charter schools have a quality education."

Excel administrators and parents who attended Thursday's vote said the board had misjudged the school.

"I'm a little baffled," said Anacostia resident Sharese Clayton, who sends her two daughters to Excel and doesn't know where they will attend next year. "This school is working for my family. If it wasn't working, trust me, I would have left. Education is very important to me."

School leaders argued the framework used by the charter school board to assess schools is biased against those with a large percentages of at-risk students. Two-thirds of Excel students are considered at-risk, meaning they receive welfare or food stamps, or are homeless or in the foster-care system.

But Naomi Rubin DeVeaux, deputy director of the D.C. Public Charter School Board, said at Thursday's vote that 22 of the city's 120 charter schools have greater at-risk populations than Excel, and most of those schools perform better on their annual assessments.

School leaders pushed back against criticism that not enough of Excel's students re-enroll. Leaders said a significant portion of their enrollment once came from the dilapidated Barry Farm public housing complex. The city started redeveloping the complex several months ago, forcing families to relocate and potentially enroll their children in different schools.

Leaders acknowledged that Excel's middle school hasn't performed as well as the elementary school, but a new middle school principal was recently appointed to help turn around those grades.

"That they can simply do it and ignore that they have a flawed tool measuring us — that's wrong not only for us, but for other charter schools that have a large portion of at-risk students," said Deborah Lockhart, chief executive officer at Excel.