A student gets help with a math problem. (Jahi Chikwendiu/The Washington Post)

Along with many Americans, I enjoy intense arguments about charter schools, the tax-supported institutions independent of school districts. I happily air my biases and skewer the squishy defenses of my foes.

People like me have to watch out for Zachary W. Oberfield, an associate professor of political science at Haverford College. He spoils our fun. On the charter school issue he is scholarly, precise and balanced.

Security? Get that guy out of here!

Oberfield’s new book is “Are Charters Different? Public Education, Teachers, and the Charter School Debate.” It is the fairest, deepest and thus most frustrating book on that subject in a long time. People on both sides of the debate will find facts in it we don’t like. That is why we should be required to read it.

Oberfield unleashes, for instance, a flood of data about how charter and non-charter teachers answer vital questions. He has responses from 35,000 teachers queried nationwide in the federal Schools and Staffing Survey; 235,000 teachers in four states who answered the Teaching, Empowerment, Leading and Learning Survey; and 1,000 teachers who responded to the Delaware Teachers Survey that Oberfield designed to explore questions not asked elsewhere.

He offers results that will please charter fans. For instance, he says that “teachers in charter schools reported greater autonomy (at least in some respects) and less red tape than do teachers in public schools” and “teachers in charter schools reported exercising greater leadership in their schools — on issues as diverse as establishing curriculum to developing professional development programming — than did teachers in public schools.”

Yet charter critics will be pleased to learn from Oberfield that those favorable reports from teachers seem to be fading and in some cases don’t reflect reality. “Initially teachers in charter schools were more likely to report higher levels of shared mission,” he says, but “in the two most recent surveys these differences evaporated.” The big four-state survey, he says, “shows that teachers in charter schools reported feeling as if they had more time to collaborate but that they did not in fact spend more time collaborating than teachers in public schools did.”

“Teachers in charter schools worked more hours for less pay than teachers in public schools did,” he says, but there were no consistent differences between charter and non-charter teachers when asked about burnout, dissatisfaction and turnover. Maybe this is because charter teachers don’t know they are working harder for less money, says the evenhanded Oberfield, or maybe because they prefer charters for other reasons.

Tempers reach dangerous levels in online arguments when the subject is whether charters should be called public schools. Oberfield gently dismisses this as a misreading of constitutional history. He acknowledges the concern “that charter schools reduce the level of democratic control over education” because their boards are usually not elected. But he also notes an attendant long-running fear — dating back to the Founding Fathers — of giving the people too much power over their political institutions. This tradition of insulating government is evident in various aspects of policymaking, he says, like the Federal Reserve’s control of interest rates and the development and implementation of regulations by federal bureaucracies.

Both sides in the debate should be cautious in citing his book’s data, Oberfield says. He finds that teachers reported “higher levels of engagement with parents and communities in charter schools,” but the explanation may be that “parents who enrolled their children in these schools were more involved in their children’s education than parents who do not.”

He sums up his results this way: “Despite some important differences, the teaching climates of charter and public schools do not match the enthusiastic expectations of proponents or the worst fears of critics.”

That’s fine. Those of us struggling over charters should be open to all points of view. And it could be that quiet, impartial words in this national debate will last longer than loud ones.

The Education Page is on hiatus and will return for the coming school year.