But stark problems remain. A recent report by the Education Research Alliance confirmed that principals engage in widespread “creaming” — selecting, or counseling out, students based on their expected performance on standardized tests. In a forthcoming study, the alliance expects to show that lowest-scoring students are less likely to move to higher-performing schools.

The rhetoric of reform often fails to match the reality. For example, Paul G. Vallas, the superintendent of the Recovery School District from 2007 to 2011, boasted recently that only 7 percent of the city’s students attend failing schools today, down from 62 percent before Katrina, a feat accomplished “with no displacement of children.” This was simply false.

Consider Joseph S. Clark Preparatory High School, one of the city’s last traditional public schools to be “taken over.” Most of its 366 students declined to re-enroll when it reopened under new management in the fall of 2011. During its first year under FirstLine, a charter management organization, Clark had only 117 “persisters,” or returning students, according to a study by Stanford University’s Center for Research on Education Outcomes, known as Credo. FirstLine could not account for where the students went after they left Clark. However, Jay Altman, its chief executive, told me in an email that before FirstLine took over, a similarly low proportion of students, about 35 percent, were returning. (The school district did not respond to my queries about Clark.)

One problem is that in the decentralized charter system, no agency is responsible for keeping track of all kids. Two years ago the Recovery School District, acknowledging that it was “worried” about high school attrition, began assigning counselors to help relocate students from schools it was closing. Louisiana’s official dropout rates are unreliable, but a new report by Measure of America, a project of the Social Science Research Council, using Census Bureau survey data from 2013, found that over 26,000 people in the metropolitan area between the ages of 16 and 24 are counted as “disconnected,” because they are neither working nor in school.

Ironically, schools like Clark actually feed the New Orleans success narrative because when bad schools are taken over their “F” grades automatically convert to a “T” — for a turnaround. Thus, in the 2013-14 school year, the four schools with “T” grades wouldn’t be counted as “failing” schools, nor would the 16 schools that received a “D” grade. About 40 percent of Recovery School District schools were graded “D,” “T” or “F” that year.

Adding to the difficulty of assessing the New Orleans experiment is the fact that Louisiana education data has been doled out selectively, mostly to pro-charter researchers, and much of the research has been flawed. Last fall, the Cowen Institute for Public Education Initiatives was forced to retract a study that concluded that most New Orleans schools were posting higher-than-expected graduation rates and test scores.

Last spring, Credo produced a study of 41 urban charter districts, including New Orleans, that purported to show that charters outperformed urban public schools on standardized test scores; but this study was also highly flawed. The methodology was based on comparing each charter student to a virtual “twin,” a composite of as many as seven public-school kids who attend “feeder” schools and who match the charter students on demographics and test scores. The problem in New Orleans was that there are virtually no local feeders left from which to draw comparisons.