Fri Feb 15, 3:00 AM ET

It looks like a typical day at a typical American grammar school: Students proceed in single file down hallways, a class of fourth-graders listens to their teacher read aloud, and students in another class work in small groups on independent projects.

But Andre Cowling, the tall, imposing new principal of Harvard Elementary on Chicago's South Side, shakes his head in wonder at it all. Last year, he says, "this wouldn't have been possible."

Harvard is one of several public schools here to get a top-to-bottom housecleaning in recent years including replacing the principal and most teachers in a bid to lift student achievement out of the nation's academic basement. The drastic approach is known as "turnaround," and Chicago is embracing it more than any US city, though it's unproven and is controversial among teachers, many parents, and students.

"It's risky in that it's new and has an untested track record," says Andrew Calkins, senior vice president at Mass Insight, a nonprofit group focused on school reform, and coauthor of a report on turnaround schools. "It's logical in that the other choice is to keep on doing what's been tried before, and we know what the results of that will be. What you try to do if you're Chicago is to minimize the risk and maximize the possibility of a good outcome" by thinking through everything that's needed to improve the climate for learning at a school.

As Principal Cowling sees it, the risk paid off. Until Harvard Elementary went through turnaround, the school was like "Beirut," he says 50 kids running through the halls at any time, holes in the floors and peeling paint on the walls, fights on or near campus, no order in the classrooms.

"Now, you can tell it's a school," Cowling says.

For an encore, the city is proposing simultaneous turnarounds at eight Chicago schools in the fall: four high schools and four elementary schools that feed into them. Even for a city that already leads the nation in school-reform ideas, the proposal is unusually bold and sweeping. Districts across the US many with schools facing reconstitution requirements under the No Child Left Behind law are watching with interest.

"We want to give families the opportunity to have a high-performing option in the neighborhood throughout [a student's] entire education," says Alan Anderson, director of the Office of School Turnaround for Chicago public schools. "There are a handful of schools that just aren't progressing at the rate we'd like them to," he says. "We know we need drastic change. It's not a decision we take lightly."

The eight schools slated for turnaround are among the worst performers in the district: At the high schools, an average student misses at least 35 days of school a year, dropout rates are above 10 percent, and the passing rate on state tests hovers at about 10 percent.

Still, some families wonder whether this will be just another reform that disrupts their kids' lives and replaces teachers they've grown close to, but yields no change in the quality of the education.

Teachers, of course, are upset about a reform that requires a school's entire staff to be let go, even if teachers can reapply.

"What kind of instability are you creating for children coming from environments that are challenging and already have instability?" asks Marilyn Stewart, president of the Chicago Teachers Union. "You're having to recruit and train teachers, and then have another turnover. No industry can survive that kind of turnover of personnel."

Ms. Stewart suggests a less drastic reform, alr