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  • Charter School Market Share And Performance

    Written on July 24, 2013

    One of the (many) factors that might help explain -- or at least be associated with -- the wide variation in charter schools’ test-based impacts is market share. That is, the proportion of students that charters serve in a given state or district. There are a few reasons why market share might matter.

    For example, charter schools compete for limited resources, including private donations and labor (teachers), and fewer competitors means more resources. In addition, there are a handful of models that seem to get fairly consistent results no matter where they operate, and authorizers who are selective and only allow “proven” operators to open up shop might increase quality (at the expense of quantity). There may be a benefit to very slow, selective expansion (and smaller market share is a symptom of that deliberate approach).

    One way to get a sense of whether market share might matter is simply to check the association between measured charter performance and coverage. It might therefore be interesting, albeit exceedingly simple, to use the recently-released CREDO analysis, which provides state-level estimates based on a common analytical approach (though different tests, etc.), for this purpose.

  • A Few Points About The New CREDO Charter School Analysis

    Written on July 1, 2013

    A new report from CREDO on charter schools’ test-based performance received a great deal of attention, and rightfully so - it includes 27 states, which together serve 95 percent of the nation's charter students.

    The analysis as a whole, like its predecessor, is a great contribution. Its sheer scope, as well as a few specific parts (examination of trends), are new and important. And most of the findings serve to reaffirm the core conclusions of the existing research on charters' estimated test-based effects. Such an interpretation may not be particularly satisfying to charter supporters and opponents looking for new ammunition, but the fact that this national analysis will not settle anything in the contentious debate about charter schools once again suggests the need to start asking a different set of questions.

    Along these lines, as well as others, there are a few points worth discussing quickly. 

  • Charter School Authorization And Growth

    Written on June 13, 2013

    If you ask a charter school supporter why charter schools tend to exhibit inconsistency in their measured test-based impact, there’s a good chance they’ll talk about authorizing. That is, they will tell you that the quality of authorization laws and practices -- the guidelines by which charters are granted, renewed and revoked -- drives much and perhaps even most of the variation in the performance of charters relative to comparable district schools, and that strengthening these laws is the key to improving performance.

    Accordingly, a recently-announced campaign by the National Association of Charter School Authorizers aims to step up the rate at which charter authorizers close “low-performing schools” and are more selective in allowing new schools to open. In addition, a recent CREDO study found (among other things) that charter middle and high schools’ performance during their first few years is more predictive of future performance than many people may have thought, thus lending support to the idea of opening and closing schools as an improvement strategy.

    Below are a few quick points about the authorization issue, which lead up to a question about the relationship between selectivity and charter sector growth.

  • A Controversial Consensus On KIPP Charter Schools

    Written on March 12, 2013

    A recent Mathematica report on the performance of KIPP charter schools expands and elaborates on their prior analyses of these schools' (estimated) effects on average test scores and other outcomes (also here). These findings are important and interesting, and were covered extensively elsewhere.

    As is usually the case with KIPP, the results stirred the full spectrum of reactions. To over-generalize a bit, critics sometimes seem unwilling to acknowledge that KIPP's results are real no matter how well-documented they might be, whereas some proponents are quick to use KIPP to proclaim a triumph for the charter movement, one that can justify the expansion of charter sectors nationwide.

    Despite all this controversy, there may be more opportunity for agreement here than meets the eye. So, let’s try to lay out a few reasonable conclusions and see if we might find some of that common ground.

  • School Choice And Segregation In Charter And Regular Public Schools

    Written on February 25, 2013

    A recent article in Reuters, one that received a great deal of attention, sheds light on practices that some charter schools are using essentially to screen students who apply for admission. These policies include requiring long and difficult applications, family interviews, parental contracts, and even demonstrations of past academic performance.

    It remains unclear how common these practices might be in the grand scheme of things, but regardless of how frequently they occur, most of these tactics are terrible, perhaps even illegal, and should be stopped. At the same time, there are two side points to keep in mind when you hear about charges such as these, as well as the accusations (and denials) of charter exclusion and segregation that tend to follow.

    The first is that some degree of (self-)sorting and segregation of students by abilities, interests and other characteristics is part of the deal in a choice-based system. The second point is that screening and segregation are most certainly not unique to charter/private schools, and one primary reason is that there is, in a sense, already a lot of choice among regular public schools.

  • Revisiting The "Best Evidence" Theory Of Charter School Performance

    Written on February 14, 2013

    Among the more persistent arguments one hears in the debate over charter schools is that the “best evidence” shows charters are more effective. I have discussed this issue before (as have others), but it seems to come up from time to time, even in mainstream media coverage.

    The basic point is that we should essentially dismiss – or at least regard with extreme skepticism - the two dozen or so high-quality “non-experimental” studies, which, on the whole, show modest or no differences in test-based effectiveness between charters and comparable regular public schools. In contrast, “randomized controlled trials” (RCTs), which exploit the random assignment of admission lotteries to control for differences between students, tend to yield positive results. Since, so the story goes, the “gold standard” research shows that charters are superior, we should go with that conclusion.

    RCTs, though not without their own limitations, are without question powerful, and there is plenty of subpar charter research out there. That said, however, the “best evidence” argument is not particularly compelling (and it's also a distraction from the positive shift away from obsessing about whether charters do or don't work toward an examination of why). A full discussion of the methodological issues in the charter school literature would be long and burdensome, but it might be helpful to lay out three very basic points to bear in mind when you hear this argument.

  • The Year In Research On Market-Based Education Reform: 2012 Edition

    Written on December 20, 2012

    ** Reprinted here in the Washington Post

    2012 was another busy year for market-based education reform. The rapid proliferation of charter schools continued, while states and districts went about the hard work of designing and implementing new teacher evaluations that incorporate student testing data, and, in many cases, performance pay programs to go along with them.

    As in previous years (see our 2010 and 2011 reviews), much of the research on these three “core areas” – merit pay, charter schools, and the use of value-added and other growth models in teacher evaluations – appeared rather responsive to the direction of policy making, but could not always keep up with its breakneck pace.*

    Some lag time is inevitable, not only because good research takes time, but also because there's a degree to which you have to try things before you can see how they work. Nevertheless, what we don't know about these policies far exceeds what we know, and, given the sheer scope and rapid pace of reforms over the past few years, one cannot help but get the occasional “flying blind" feeling. Moreover, as is often the case, the only unsupportable position is certainty.

  • Are Charter Caps Keeping Great Schools From Opening?

    Written on October 3, 2012

    ** Reprinted here in the Washington Post

    Charter school “caps” are state-imposed limits on the size or growth of charter sectors. Currently, around 25 states set caps on schools or enrollment, with wide variation in terms of specifics: Some states simply set a cap on the number of schools (or charters in force); others limit annual growth; and still others specify caps on both growth and size (there are also a few places that cap proportional spending, coverage by individual operators and other dimensions).

    A great many charter school supporters strongly support the lifting of these restrictions, arguing that they prevent the opening of high-quality schools. This is, of course, an oversimplification at best, as lifting caps could just as easily lead to the proliferation of the many unsuccessful charters. If the charter school experiment has taught us anything, it’s that these schools are anything but sure bets, and that even includes the tiny handful of highly successful models such as KIPP.*

    Overall, the only direct impact of charter caps is to limit the potential size or growth of a state’s charter school sector. Assessing their implications for quality, on the other hand, is complicated, and there is every reason to believe that the impact of caps, and thus the basis of arguments for lifting them, varies by context – including the size and quality of states’ current sectors, as well as the criteria by which low-performing charters are closed and new ones are authorized. 

  • Student Attrition Is A Core Feature Of School Choice, Not A Bug

    Written on August 27, 2012

    The issue of student attrition at KIPP and charter schools is never far beneath the surface of our education debates. KIPP’s critics claim that these schools exclude or “counsel out” students who aren’t doing well, thus inflating student test results. Supporters contend that KIPP schools are open admission with enrollment typically determined by lottery, and they usually cite a 2010 Mathematica report finding strong results among students in most (but not all) of 22 KIPP middle schools, as well as attrition rates that were no higher, on average, than at the regular public schools to which they are compared.*

    As I have written elsewhere, I am persuaded that student attrition cannot explain away the gains that Mathematica found in the schools they examined (though I do think peer effects of attrition without replacement may play some role, which is a very common issue in research of this type).

    But, beyond this back-and-forth over the churn in these schools and whether it affected the results of this analysis, there’s also a confusion of sorts when it comes to discussions of student attrition in charters, whether KIPP or in general. Supporters of school choice often respond to “attrition accusations” by trying to deny or downplay its importance or frequency. This, it seems to me, ignores an obvious point: Within-district attrition - students changing schools, often based on “fit” or performance - is a defining feature of school choice, not an aberration.

  • The Unfortunate Truth About This Year's NYC Charter School Test Results

    Written on July 23, 2012

    There have now been several stories in the New York news media about New York City’s charter schools’ “gains” on this year’s state tests (see hereherehere, here and here). All of them trumpeted the 3-7 percentage point increase in proficiency among the city’s charter students, compared with the 2-3 point increase among their counterparts in regular public schools. The consensus: Charters performed fantastically well this year.

    In fact, the NY Daily News asserted that the "clear lesson" from the data is that "public school administrators must gain the flexibility enjoyed by charter leaders," and "adopt [their] single-minded focus on achievement." For his part, Mayor Michael Bloomberg claimed that the scores are evidence that the city should expand its charter sector.

    All of this reflects a fundamental misunderstanding of how to interpret testing data, one that is frankly a little frightening to find among experienced reporters and elected officials.



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