AMID extensive coverage of the very real challenges facing our public schools, we shouldn't lose sight of what's actually working. Right now, outstanding educators are working closely with families of all backgrounds to transform Philadelphia's lowest performing schools into some of the best schools in the city. Yet, not enough people are talking about Renaissance schools.

Philadelphia's turnaround efforts began nearly a decade ago when Mastery Charter Schools assumed management of three chronically failing schools: Thomas, in South Philadelphia; Shoemaker, in West Philadelphia; and Pickett, in Germantown.

Nearly nine years later, how are they shaping up? Math proficiency has increased by at least 50 percentage points, and reading proficiency has increased at least 30 percentage points. These extraordinary academic gains - far outpacing the rest of the city - were accomplished in the same buildings, serving the same families as before the turnaround.

Most important, graduates are realizing postsecondary opportunities.

Jenny Sak, a Mastery Thomas graduate and now a student at Penn State, credits her school's turnaround for her success. "All of the teachers [at Thomas] wanted you to succeed," she said. "They didn't give up on you even if you wanted to give up on yourself. Applying to five different schools as a graduation requirement opens your mind to looking at colleges."

Today, some 20 communities across the city are partnering with a turnaround charter-school operator.

In a report released by the school district last month, we learned that Renaissance turnaround charters:

Improved academics. More students are reading and doing math on grade level.

Increased safety. Schools had 42 percent fewer serious incidents after turnaround.

Serve the same students as the previously low-performing school. Retention increased and the turnaround schools serve a higher proportion of students with special needs.

In total, more than 20,000 students and their families have benefited from this effort, and thousands of young people - who otherwise might not have graduated - are on a path to college or meaningful work.

These data tell only part of the story. Families in such neighborhoods as Frankford, Kingsessing and Hunting Park are seeing the positive impact of school turnarounds.

"The turnaround at Mastery Gratz High School has really meant a lot to the Gratz community," said Maritza Guridy, a Gratz parent. "Tough and serious choices had to be made for our children and their future. Despite our growing pains, I can attest to the fact that the change has been a positive one and that there are students who are now getting their rightful education."

So, why aren't we turning around more of Philadelphia's struggling schools if this approach is working? Many critics point to the cost of charters to the financially strapped district, but the data show that turnaround schools are more efficient than traditional charters. They also reduce the underutilization that has made it impossible for many of our district schools to achieve efficiencies, and, as charter schools, they have the flexibility to allocate resources in a way that will ensure the most benefit to students.

The facts show that charter turnarounds are working in Philadelphia. Students and families say they're working. Dollar for dollar, it's the most efficient way to dramatically improve neighborhood schools. Successful operators are ready to serve more students and communities.

With thousands of students still in schools that fail to provide an adequate education, the school district has a responsibility to begin the turnaround of more schools, immediately. It should set a goal to transform every one of Philadelphia's most persistently violent and academically failing schools over the next three years.

Helen Cunningham chairs the Philadelphia School Partnership's School Investment Committee and is the executive director of the Samuel S. Fels Fund, and Mark Gleason is the executive director of the Philadelphia School Partnership.