Detroit is not only the lowest in this group of lowest-performing districts on the math and reading scores, it is the lowest by far. One well-regarded study found that Detroit’s charter schools performed at about the same dismal level as its traditional public schools. The situation is so bad that national philanthropists interested in school reform refuse to work in Detroit. As someone who has studied the city’s schools and used to work there, I am saddened by all this.

The situation is not entirely Ms. DeVos’s fault, of course, but she is widely seen as the main driver of the entire state’s school overhaul. She devised Detroit’s system to run like the Wild West. It’s hardly a surprise that the system, which has almost no oversight, has failed. Schools there can do poorly and still continue to enroll students. Also, after more than a decade of Ms. DeVos’s getting her way on a host of statewide education policies, Michigan has the dubious distinction of being one of five states with declining reading scores.

In contrast, consider the case of New Orleans, where virtually all the schools are charters. Here, the state has taken over about a third of charter schools because of poor results since the system was revamped in the wake of Hurricane Katrina. Also, while the system initially had limited oversight and worked poorly, local leaders now take extensive steps to facilitate a fair process of school choice, help prevent schools from cherry-picking students and manage a centralized student expulsion system. In other words, the system provides some oversight to help ensure that families have good schools to choose from.

The New Orleans results have been impressive. In the decade after the reforms, the city’s standardized test scores have increased by eight to 15 percentile points and moved the district from the bottom to almost the state average on many measures. High school graduation and college entry rates also seem to have improved significantly, even while suspensions, expulsions and the rate of students switching schools have all dropped. Detroit and New Orleans represent radically different versions of school choice — and the one that seems to work is the one that uses the state oversight that Ms. DeVos opposes.