Most parents know who are the great teachers in their schools and who are the teachers to avoid.

So on one level the resistance to evaluating teachers more systematically, rewarding good ones and encouraging bad ones to leave, is puzzling.

Evaluation advocates, like the leaders of D.C. Public Schools, say: Measure how well a student reads at the beginning of the year and measure again at the end. Teachers whose students improve should get raises; teachers whose students aren’t learning should find new careers. Test scores shouldn’t be the only factor, but they should be a substantial one.

Contrary to what many critics argue, the growth model of evaluation doesn’t ask a teacher to compensate for everything a poor child may be missing — parental involvement, books in the home, good nutrition, proper eyeglasses. It compares teachers with their peers in how much improvement they can encourage among comparable groups of children.

But some critics offer more nuanced questions. Should performance be averaged over two or three years? How do you measure the impact of teachers in subjects that aren’t tested, such as art or music? Is it fair to compare a teacher ably supported by a guidance counselor, principal and reading specialist to those teachers left to fend for themselves?

I think those are solvable problems. Most organizations manage to evaluate employee performance despite the presence of hard-to-quantify variables.

But there’s a way to sidestep those problems, too, or at least take them out of the hands of unwieldy bureaucracies: Just leave it to the school.

Under this model, parents would be given comparable information about a host of available schools. They could send their children to schools that are succeeding and avoid those that are failing. School leaders would be free to hire, evaluate and reward staff as they thought best, with no bureaucratic interference. But if they failed to develop and retain talented teachers, they also would fail to attract enough students, and their schools would go out of business.

This model exists. It’s called charter schools. In post-Katrina New Orleans, as my colleague Jo-Ann Armao recently described on this page, more than 80 percent of students are in charters, and they are doing better than before Hurricane Katrina. In the District of Columbia, 31,562 students — 41 percent of public school children — attend one of 53 public charter schools (on 98 campuses). Enrollment has been growing 7 or 8 percent per year. On current trends, more than half of D.C. students will be in charter schools within a few years.

The District has been fortunate, since 1996, to have a law that promotes charter school quality and independence. It’s been fortunate in the caliber of the board, now chaired by attorney Brian Jones, and its executive directors — for many years Josephine Baker and, since January, Scott Pearson, fresh from Arne Duncan’s Education Department.

The schools cannot pick and choose their students. Parents pick their schools, and if there is a waiting list admission is random (with a preference only for siblings of enrolled students and children of a school’s founding board members). Charter school students are, on average, poorer than traditional school students, but their performance is impressive.

The board grades all charter schools and posts results. Criteria include student proficiency, both absolute and growth over time; attendance and re-enrollment rates; and “gateway measures” — how well students read as they prepare for middle school, their math proficiency as they approach high school and their PSAT and SAT scores and graduation rates as they head to college.

One school gave up its charter in 2011 because of low enrollment; two gave up their high school programs; and the board revoked two charters, one each for financial and academic reasons. Meanwhile, innovative operators continue to seek permission to open schools here.

The schools operate inside a clearly defined structure, in other words. But within that structure, they have freedom — including to attract, evaluate, retain and dismiss teachers as they see fit.

Charter schools and unions could (and in a few places do) co-exist, with contracts that set reasonable floors for salaries, for example, and assure due process for dismissals. But charter schools could not thrive with the kind of detailed contracts that limit principal discretion in staffing schools, standardize how many minutes teachers can work each day and on which tasks, and, in many cities, prevent teachers from being judged on results.

There’s no panacea in public education. Not all charter schools succeed, and Washington will be better off if Chancellor Kaya Henderson and her team manage to improve the traditional public school system too.

But a well-run charter system ought to find supporters among both advocates of school choice and people who worry that teacher evaluation will grow too rigid.

fredhiatt@washpost.com