A new report by Mathematica Policy Research Inc. and the Center on Reinventing Public Education, which analyzes the supposed benefits of private, nonprofit charter school management operations, has highlighted interesting trends in the U.S. charter movement. The report – Charter-School Management Organizations: Diverse Strategies and Diverse Student Impacts – was reviewed for the Think Twice review project by the National Education Policy Center. And while the review praised the report for offering an objective assessment of the benefits for middle-school teachers and students, it has also noted that the report’s analytic approach relied on a highly selective slice of all Charter management organizations (CMOs) operating nationwide, using just 22 of 130 CMOs that qualified for the study sample. CMOs are nonprofit firms that operate multiple charter schools either directly or through management contracts, accounting for about one-fifth of the nation’s more than 5,000 public charter schools. The review questioned the “generalizability” of the findings, as many CMOs serve urban students from low-income families. These schools are typically smaller and give more frequent coaching and mentoring of teachers and more intensive use of student test results and other achievement data to evaluate teachers. The review also criticized the report’s “tortured” attempts to find achievement advantages in the CMO-run schools, as the analysis began with the more than 130 CMOs operating nationwide and then engaged in the successive narrowing of the CMOs down to just 22 that met the criteria. From those 22, the report found that a small number of CMOs boosted middle-school student achievement growth at discernible levels, said review author Professor Bruce Fuller of the University of California-Berkeley. “Once thus narrowed, the study presents impressive results for between 4 (reading outcome) and 7 (math outcome) of the 22 CMOs,” Fuller observes. “So, to whom or what can we generalize these results?” Moreover, the overall effects of CMOs on student achievement were largely flat when compared with both traditional public schools and with a comparison sample of independent charter schools not affiliated with a CMO. “What’s disappointing for charter-school adherents is the bottom line that the average effects of attending a CMO-run charter school are not significantly different from those of attending a regular public school.” He criticizes the report for what he calls its “unrelenting search for achievement effects in a small, selective subset of sampled CMOs,” which he states “erodes its credibility.” Despite these criticisms, Fuller concludes that the report does offer illuminating insights into features of successful CMOs. “This report gets us a bit closer toward pinpointing highly effective CMOs and the practices or resources that may help to explain their efficacy. “What is not known is whether these practices or resources can be exported with integrity to other charter companies or to the wider public school system. These questions should be squarely addressed in future research.”