The idea of mayors taking over school districts is very much in vogue right now. It's happened in New York, Boston, Chicago, Cleveland and a long list of other cities where the schools were an obvious problem. The motivation for mayors is clear. They recognize that they will be blamed for poor school performance even when they have no control over the system, so they might as well get some control. And most seem convinced they will never attract and maintain a stable middle class without decent schools. "If the city is going to succeed, you have to have education working," says Nashville Mayor Bill Purcell. "Mayors who by design or default have avoided education can't anymore."

That's all well and good for the mayors--but what about the schools? A new study, underwritten by the U.S. Department of Education and several foundations, suggests that mayoral control really can make a positive difference in both district management and student performance.

In "The Education Mayor," Brown University education professor Kenneth Wong and his colleagues compared 14 districts run by mayors with 90 similar districts still run by independent school boards. They claim that mayoral control translates into one-third of a year's worth of extra learning by the average child. "These are real gains in terms of moving the test scores in a positive direction," Wong says.

Most mayors who assume control over the local schools want to shift resources away from central administration bureaucracy and toward classroom instruction. Wong's study suggests they've been pretty successful at this. They've been less successful at altering other bureaucratic habits, such as school staffing patterns.

In political terms, what a takeover by City Hall essentially does is make the superintendent part of the mayor's staff, rather than someone who answers to an elected board. That alone can have its benefits. In Boston--a pioneer in the mayoral takeover movement--the old school board had gone through three superintendents in five years. That wasn't so unusual for an urban district. What was unusual was that after Mayor Thomas Menino won control of the schools, he stuck with the same superintendent for the next 11 years with good results.

There simply aren't enough districts run by mayors for any study to prove that change in leadership necessarily leads to change in learning. Nobody anywhere--mayor or school board--has a magic formula for figuring out how to convert bad schools into good ones. But anecdotal evidence and now formal research seem to suggest that a mayor committed to improving schools can bring about greater stability and accountability. That's not a solution, but it's a step forward.