As a long time charter school agnostic (if not outright athiest) I have to admit that my worldview was initially shaken when I read about a new study that seems to show that New York charter schools outperform traditional public schools (old news) even when you try to account for the "creaming" effect (new news). This is pretty big stuff. The study compared the educational outcomes of students who won spots in charter school libraries to students who applied for spots via the lottery, but did not win and get a seat. This is designed to eliminate the selection bias that comes from only studying those kids whose parents are involved enough to apply for a charter seat versus those whose parents may not be involved at all.
Now, as with all things, it's possible to pick the study apart with tweezers. You could say that there are some questions as to whether the study really meets the "gold standard" it claims to (thanks Gotham Schools). You could point out that a nationwide study of charter schools found that only a small percentage of charters outperform their traditional peers. You could say that similar studies on the DC voucher program showed no difference. You could even say that any study measuring student learning based on standardized tests is really measuring test-taking skills more than learning and therefore should be disregarded.
You could say all of those things and some of them may even be valid. But the research is showing here that New York charter schools are doing pretty well. So maybe we got a disproportionate number of that 17% of effective charter schools nationwide. I suppose that's possible. But ultimately, I think it may also be beside the point.
The question I always ask when I see a study like this is: "What makes these schools better?" I still find it hard to believe that their very charter-ness conveys some special educating ability that other schools lack. These schools are doing something in their classrooms that is helping their children learn. If we want to replicate it across a wide range, we need to know what it is.
Unfortunately, study author Caroline Hoxby doesn't know. (Which is fine, since that wasn't really what she was studying.) The point here is that we need to find out what the difference maker really is and then replicate it as far and wide as we possibly can. Let's stop slugging it out over charter schools and look at what works. If that means more charter schools, then fine. If that means taking some charter practices and applying them in traditional schools, let's do it. Either way, now is not the time to sit smugly or petulantly because of the results of some survey. Let's start looking at what we can find that will bring results for the kids. Those are the results that matter.