Initial assessments were mixed. In the early days, charter authorizing was very loose, nobody knew what worked best, and lots of weak schools were launched. The system has since tightened. In Washington, D.C., for instance, seven out of nine requests to open new charters are now turned down, and 41 charters have been closed for failing to produce good results.
Nationwide, 561 new charter schools opened last year, while 206 laggards were closed. Unlike conventional public schools, the charter system allows poorly performing schools to be squeezed out.
As charter operators have figured out how to succeed with children, they are doubling down on the best models. Successful charter schools have many distinctive features: longer school days and longer years, more flexibility and accountability for teachers and principals, higher expectations for students, more discipline and structure, more curricular innovation, more rigorous testing. Most charter growth today is coming from replication of the best schools. The rate of enrollment increase at high-performing networks is now 10 times what it is at single-campus “mom and pop” academies.
The combination of weak charters closing and strong charters replicating is having powerful effects. The first major assessment of charter schools by Stanford’s Center for Research on Educational Outcomes found their results to be extremely variable, and overall no better than conventional schools as of 2009. Its follow-up study several years later found that steady closures and their replacement by proven models had pushed charters ahead of conventional schools. In New York City, the average charter-school student now absorbs five months of extra learning a year in math, and one extra month in reading, compared with counterparts in conventional schools.
Other reviews show similar results, and performance advantages will accelerate in the near future. Charter schools tend to start small and then add one additional grade each year. Thus many charters in New York and elsewhere are just getting started with many children. As the schools mature, and weak performers continue to be replaced, charters will become even more effective.
But the results top charter schools are achieving are already striking. At KIPP, the largest chain of charters, 86% of all students are low-income, and 95% are African-American or Latino, yet 83% go to college. In New York City, one of the academies Mr. de Blasio has denied additional space to is Harlem’s highest-performing middle school, with its 97% minority fifth-graders ranking No. 1 in the state in math achievement. It and the 21 other schools in its charter network have passing rates on state math and reading tests more than twice the citywide average.
Judged by how far they move students from where they start, New York charter schools like Success Academies, Uncommon Schools, Democracy Prep and Achievement First—and others like them across the country—are now the highest-achieving schools in America. The oft-heard claim that charters perform no better than conventional schools on the whole is out of date and inaccurate.