CAMBRIDGE, Mass. -- A nationwide study of 100 urban school districts, including Pittsburgh, shows that when mayors control the school boards, students and their schools likely are better off.

That was a conclusion by two researchers who released their findings at a conference here at Harvard University yesterday.

"Based on our data, we believe that the mayor-appointed school board will improve student performance," said Kenneth K. Wong, a Vanderbilt University professor and nationally known education researcher.

He highlighted student test scores in Cleveland, where the percentage of fourth-graders who scored "proficient" in reading and math nearly doubled after the mayor replaced that city's famously dysfunctional elected school board with an appointed board.

Similar gains occurred in Boston and Chicago when those school boards became mayor-appointed, according to Wong. However, increases were minimal in the mayor-controlled school districts of Baltimore and Detroit.

Still, said Wong, "We think the results are moving in the right direction."

A commission appointed by Pittsburgh Mayor Tom Murphy last month recommended that city residents should stop electing their school board members and instead support a mayor-appointed board. That would require an act of the state Legislature.

The controversial recommendation by the Mayor's Commission on Public Education -- and its highly critical report of the current school board and the district's future -- is opposed by the city's teacher union.

City school board members and administrators, however, have yet to comment on the report. Pittsburgh schools spokeswoman Pat Crawford said yesterday a formal response is being prepared.

At yesterday's national conference on "School Board Politics" sponsored by Harvard's John F. Kennedy School of Government, Wong and fellow Harvard researcher Francis X. Shen also said they found better budget practices among mayor-appointed school boards.

Appointed school boards generally are more likely to spend money on instruction and direct services such as new reading programs and vision testing for students, Wong said, rather than administrative or "central office" costs.

"They seem to be more fiscally responsible," he said.

Also significant was the mayor-appointed board's greater ability to get more federal money for their districts, Wong said. His study suggests that "mayors are keen on using their lobbying capacity to negotiate for federal grants."

Wong said a common argument against the mayor-appointed system of school governance is that, because of other distractions and duties, mayors won't focus on the school district's poorest and neediest students.

"We found that is not the case," said Wong. "Usually [mayors] promote the fact that they can reallocate funds to the neediest schools."

And a mayor-appointed board member can be easily and quickly replaced -- unlike elected board members, Wong said. "It seems to me they are going to be held more accountable for results."

The study also looked at community involvement in mayor-appointed school districts. "There are a lot of skeptics out there" who believe that city residents will no longer feel connected to their school district if they can't vote for their board members, said Wong. "We found this is not true."

But the researchers cautioned that mayor-appointed boards can't necessarily improve all districts in all areas. "This is no silver bullet," said Shen. He noted that while some districts saw great improvement in test scores under a mayor-controlled board, "these districts were at a low level of performance to begin with."

Murphy's commission report is referenced on the first page of the study by Wong and Shen. But Wong, who has served as an adviser to state and local school systems, said no Pittsburgh officials or mayor's commission members have contacted him about his research.

He said he hopes to expand his school board study when -- or if -- Pittsburgh and other districts nationwide move to the mayor-appointed form of school leadership.

The study was funded through the Mid-Atlantic Regional Educational Laboratory, a U.S. Department of Education research center. The full report can be found under "conference papers" at www.ksg.harvard.edu/pepg.