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Lessons And Directions From The CREDO Urban Charter School Study


As always, a very perceptive article by Mathew DiCarlo. I particularly like your suggestion about concentrating on what educational treatments work the best (or worst) which was the initial justification for charter schools. One major point which elaborates on some of the comments in the article: It is important to put the effect size of 28 and 40 days of additional instruction in perspective because politically and in the media this latest study is being touted as demonstrating that overall urban charter schools public schools by significant amounts. These effect sizes are actually tiny--.05 of a standard deviation (SD) in reading and .04 in math as reported in the CREDO study itself.(although they did hype the results by reporting these results as “significant” which in statistical terms just means “not by chance”--a term usually misunderstood by the public and media as "substantial" or worth noting. The usual floor in the research community for an educational intervention to be noteworthy is .4 of a standard deviation--a multiple 8 to 10 times the effect size CREDO found. To give a sense of the magnitude of CREDO's findings, a full standard deviation difference in test performance translates to roughly 2-3 years of additional instruction (according to John Hattie) or 20 to 30 times the charter advantage found by CREDO. John Hattie in his book Visible Learning for Teachers listed the effect size of 150 of the most popular school improvement interventions by using meta-analysis of 150,000 research studies involving 250 million students. He found numerous individual programs near or above the 1.0 SD level such as visible learning (making children’s thinking and understanding transparent and enlisting students in the educational process) 1.44SD, formative evaluation .9 SD, response to instruction (early intervention after good first teaching) 1.07SD, and classroom discussion .82SD. Many more were close to that range and 69 were above the .4 SD standard. Many of these high-scoring programs and ideas are staples of the Common Core active classroom approach, currently used in a multitude of non-charter public schools (and some charter schools) and a clear rebuttal to the claims that only charters and the competitive pressure they engender can produce improvements in public education. Charter schools were in the bottom range (114 out of 150 improvement strategies evaluated) of Haddie’s effect size list with almost no advantage over expected normal growth. Mathew's major point that we should be looking at which treatments whether in charters or non-charters produce the most improvements (remembering that test results give only a partial picture of educational attainment) is right on target.

It would be interesting to get your current summary on what we know, as of know, about the question you define - why? FWIW, an insightful article that tries to answer part of that question: What's interesting is that if we could move the discussion from whether to why, we could start to focus on how to apply the lessons in the schools in large districts that educates every child. - How do we create a positive peer environment? - What pedagogical approaches are most promising? - What about spending or other resources?

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