A vocal supporter of mayoral control says that though he’s an economist, it’s tough for him to base his belief in the school governance structure on numbers.

Marcus Winters, a fellow at the Manhattan Institute for Policy Research who has touted Mayor Bloomberg’s school reforms in newspaper op/eds and academic papers, says mayoral control is the best way to govern schools because it provides more accountability for education reforms — but he can’t prove that using test scores.

“It makes me a little queasy to talk about researching positive effects of mayoral control,” Winters said today in a meeting with reporters about the governance structure. He said it’s “inappropriate” to draw a correlation between student performance and mayoral control because mayoral control is a broad governance structure, not a specific reform. “It’s really difficult to study because there’s a period before mayoral control and a period after, but other things have changed in the world besides mayoral control in that time,” he said.

Because mayors who take control of schools are typically very interested in reforming education, it’s hard to attribute the success of their reforms solely to the structure of mayoral control, Winters said. Once a third or fourth mayor takes the helm of the school system (something that hasn’t yet happened in many of the mayoral control cities), it will be easier for researchers to look at the effects of the system independently from the personalities who govern them, he said.

Many supporters of mayoral control, including Learn NY, the organization lobbying to preserve it, point to gains in test scores since Mayor Bloomberg and Chancellor Klein took over as proof the structure is working (though some argue test scores began improving before mayoral control was instituted).

Winters says mayoral control is good governance because under the structure, citizens know exactly who is responsible for decisions about schools. Centralizing such a large budget and system under the mayor also throws a “spotlight” on education, making it a more visible, bigger issue, he argues. (For more on his views on mayoral control, see Winters’ op-ed in the New York Post from October, or an AfterEd TV interview with him.)

“The way I think about mayoral control isn’t ‘Are Bloomberg and Klein good?’ but, what system can we use that’s most likely to develop effective policies?” he said today.