07/24/2012 10:32 am ET | Updated Sep 23, 2012

A Tale of Two Schools: What New York Department of Education Is Getting Right

If there's ever a tangible physical reminder about the differences in education quality in a particular locale, it is found on the floors of a school building on West 134th Street in Harlem. Literally on the floors. There, a line of tape runs down the hallways. On one side is Democracy Prep Charter School, which in 2010 was the best middle school in New York City according to the annual chancellor's Progress Report. On the other side, until recently, was the Academy of Collaborative Education, which that year happened to be the worst middle school.

Limited physical space in New York and other urban areas means multiple schools share a single building, an occurrence termed "co-location." Eight-hundred-ninety-five schools (out of more than 1,700 in the city) share 328 buildings. And it's not just charter schools sharing with district schools, but district schools sharing with one another.

It's a remarkably complex and contentious issue, bundling up all at once questions of school funding, budget and cost constraints, space and other resource restrictions, equitable funding and disparities in student achievement.

Co-location is often seen as a symbol of what is wrong in public education. In the particular instance of Democracy Prep and ACE, however, co-location offers a tale not of what's wrong about the state of public education, but about what's right -- about what happens when accountability works, when consistently failing schools are shut down and good schools are allowed to expand.

Briefly, the story is this. The first campus of Democracy Prep (the network now has seven schools) opened in 2006 -- the exact same time the New York City Department of Education opened ACE. In hindsight, the case offers about as close to a scientific experiment as is possible in K-12 education: two brand new schools, both teaching about 100-125 6th grade students, located in the same building, with the same kinds of students, all from Harlem. It's worth reminding that charter schools like Democracy Prep do not hand-select students. They are chosen via a random lottery.

From day one, the two middle schools moved in opposite directions in terms of student performance (as measured by the DOE chancellor's annual Progress Report) and parent and student satisfaction (as measured by NYC School Surveys). A short three years in, in 2009, ACE received a "D" score on the chancellor's Progress Report and was ranked the worst middle school in central Harlem, while Democracy Prep received an "A" and was ranked the best.

That year, DOE put ACE, which had moved in a consistently negative direction in terms of student learning and safety, on a school closure list with 18 other failing schools. But the United Federation of Teachers, the city's largest teachers union, joined with the NAACP and other groups to sue to keep ACE open, arguing that DOE had "failed to indicate the ramifications of the school closings."

Initially, the court ruled in favor of the UFT, and ACE was granted a lifeline. It was short-lived. By the end of the 2009-2010 academic year, ACE was ranked the worst middle school not only in Harlem but in all of New York City, while Democracy Prep had improved to the top middle school -- again, not just in Harlem, but in the entire city.

It was at this point that the disparities began to attract the attention of local news. By July 2011, the courts reversed their decision and allowed 22 persistently failing schools to be shut down, including ACE.

At the same time, Democracy Prep has expanded, opening a second middle school, Democracy Prep Harlem, in 2010 with 109 students. DOE located Democracy Prep Harlem in the exact same space that ACE once occupied, meaning it now serves similar students, in the same community, in the same building, but with massively different results. (And to be clear that this isn't a case of DOE blindly giving preference to charter schools over zoned neighborhood schools. There is another middle school -- PS 92, a sort of average "B"/"C" rated school -- located with Democracy Prep in the same building on West 134th Street. In other words, DOE concentrated their accountability efforts on the truly persistently failing schools.)

Two takeaways:

First, in a local setting, we now have a groundswell of high-performing charter schools in Harlem. Continued growth for Democracy Prep means, starting this year, all students in Harlem who want a kindergarten or sixth grade seat at a Democracy Prep campus will have one. Overall, New York City education blog Gotham Schools reports that "half of the 1,700 District 5 sixth-grade students will attend charters" in 2012. This makes Harlem an incredible case study for the proliferation of top charter schools.

Second, more broadly, is that this story serves as an example of a successful accountability. The process of shutting down a school is undoubtedly hard. But when accountability works as intended, consistently low-performing schools are identified; a district is bold enough to take on and win a lawsuit to shut those schools down; better schools are allowed to expand to fill the void; and students, ultimately, are moved from low- to high-performing schools.