Obama's salute to a New Orleans charter school

President Obama's visit to a charter school in post-Katrina New Orleans today is just one more indication that these nontraditional schools are finally getting the validation they deserve. This, after nearly 20 years of scrutiny as publicly funded but privately run schools.

The Obama administration is heavily promoting more of these hybrid schools. As part of a $4.35 billion education-reform initiative, the president plans to reward states that make it easier to start charter schools that often serve inner-city children. Eleven states still don't allow charters.

The school visited by the president, the Dr. Martin Luther King Jr. Charter School for Science and Technology, educates mainly poor African-American children. It stands out as a success story, along with other New Orleans charters, when compared with the city's traditional public schools, which are still largely classified as failing.

States such as Tennessee, Illinois, and Louisiana have responded to the administration's incentive by removing limits on the number of charter schools. Other states are moving in the same direction. That's good news for successful charter operators, such as the Kipp Academies, which want to expand. Nationwide, about 1.5 million kids – many of them poor and minority students – attend about 4,600 charter schools.

Teachers unions, however, chafe at the mostly nonunion schools. They decry the schools' ability to fire low performing teachers at will, and to pay according to performance instead of seniority and credentials. When charters show success, the unions argue it's because the schools skim off the most motivated kids (and their parents).

A September study puts that argument to rest. The study examined New York City charter schools that determine admission by lottery. It found that students randomly chosen to attend the charters performed better on state exams than those who were not chosen and had to attend the city's public schools.

No skimming the cream there. The study, conducted by economist Caroline Hoxby of Stanford University in Palo Alto, Calif., removed bias by relying on random samples of two groups of students who wanted to go to charters.

Ms. Hoxby also found that New York City kids who stayed in charters from kindergarten through eighth grade almost matched their peers in white affluent suburbs in math. They did less well in English, but still closed 66 percent of the gap.

The study reaffirms the value of a school's freedom to innovate. It did not conclude that charter characteristics such as a longer school year, merit pay for teachers, or more time on English lessons caused higher achievement. But it did find a correlation.

Not all charters are equal, and other studies show mixed results. But states must take charters more seriously as an alternative to failing public schools. They must measure and monitor them – and learn from them.