This comes from the NYT article I posted immediately below; it’s of particular interest because if you wanted to design a scientific experiment in educational reform, you’d have a hard time beating this real-world example.

A building on 118th Street [in Harlem] is one reason that the parents who are Perkins’s constituents know that charters can work. On one side there’s the Harlem Success Academy, a kindergarten-through-fourth-grade charter with 508 students. On the other side, there’s a regular public school, P.S. 149, with 438 pre-K to 8th-grade students. They are separated only by a fire door in the middle; they share a gym and cafeteria. School reformers would argue that the difference between the two demonstrates what happens when you remove three ingredients from public education—the union, big-system bureaucracy and low expectations for disadvantaged children.

On the charter side, the children are quiet, dressed in uniforms, hard at work—and typically performing at or above grade level. Their progress in a variety of areas is tracked every six weeks, and teachers are held accountable for it. They are paid about 5 to 10 percent more than union teachers with their levels of experience. The teachers work longer than those represented by the union: school starts at 7:45 a.m., ends at 4:30 to 5:30 and begins in August. The teachers have three periods for lesson preparation, and they must be available by cellphone (supplied by the school) for parent consultations, as must the principal. They are reimbursed for taking a car service home if they stay late into the evening to work with students. There are special instruction sessions on Saturday mornings. The assumption that every child will succeed is so ingrained that (in a flourish borrowed from the Knowledge Is Power Program, or KIPP, a national charter network) each classroom is labeled with the college name of its teacher and the year these children are expected to graduate (as in “Yale 2026” for one kindergarten class I recently visited). The charter side of the building spends $18,378 per student per year. This includes actual cash outlays for everything from salaries to the car service, plus what the city says (and the charter disputes) are the value of services that the city contributes to the charter for utilities, building maintenance and even “debt service” for its share of the building.

On the other side of the fire door, I encounter about a hundred children at 9:00 a.m. watching a video in an auditorium, having begun their school day at about 8:30. Others wander the halls. Instead of the matching pension contributions paid to the charter teachers that cost the school $193 per student on the public-school side, the union contract provides a pension plan that is now costing the city $2,605 per year per pupil. All fringe benefits, including pensions and health insurance, cost $1,341 per student on the charter side, but $5,316 on this side. For the public-school teachers to attend a group meeting after hours with the principal (as happens at least once a week on the charter side) would cost $41.98 extra per hour for each attendee, and attendance would still be voluntary. Teachers are not obligated to receive phone calls from students or parents at home. Although the city’s records on spending per student generally and in any particular school are difficult to pin down because of all of the accounting intricacies, the best estimate is that it costs at least $19,358 per year to educate each student on the public side of the building, or $980 more than on the charter side.

But while the public side spends more, it produces less. P.S. 149 is rated by the city as doing comparatively well in terms of student achievement and has improved since Mayor Michael Bloomberg took over the city’s schools in 2002 and appointed Joel Klein as chancellor. Nonetheless, its students are performing significantly behind the charter kids on the other side of the wall. To take one representative example, 51 percent of the third-grade students in the public school last year were reading at grade level, 49 percent were reading below grade level and none were reading above. In the charter, 72 percent were at grade level, 5 percent were reading below level and 23 percent were reading above level. In math, the charter third graders tied for top performing school in the state, surpassing such high-end public school districts as Scarsdale.

Same building. Same community. Sometimes even the same parents. And the classrooms have almost exactly the same number of students. In fact, the charter school averages a student or two more per class. This calculus challenges the teachers unions’ and Perkins’s “resources” argument—that hiring more teachers so that classrooms will be smaller makes the most difference. (That’s also the bedrock of the union refrain that what’s good for teachers—hiring more of them—is always what’s good for the children.) Indeed, the core of the reformers’ argument, and the essence of the Obama approach to the Race to the Top, is that a slew of research over the last decade has discovered that what makes the most difference is the quality of the teachers and the principals who supervise them. Dan Goldhaber, an education researcher at the University of Washington, reported, “The effect of increases in teacher quality swamps the impact of any other educational investment, such as reductions in class size.”