As I’ve written before, every stripe of education charlatan has been cherry-picking PISA data to support whatever policies he or she prefers. From Diane Ravitch’s obsession with imitating Finland to Marc Tucker’s divining of lessons from the “top performers,” we’ve seen a host of causal claims attributed to the relationship between PISA results and particular practices or policies that are not causal at all.
Over on the Education Next blog, Matt Chingos has a brilliant piece demonstrating the relationship between Christmas spirit and student achievement. Matt even runs some regressions to “prove” his point — something that Diane Ravitch, Marc Tucker, and most other “best practices” gurus can’t or don’t bother doing. Apparently, spending more on Christmas shopping “predicts” higher student achievement, controlling for some demographic factors. Clearly, we don’t need smaller classes or better teacher-training to make schools better, we just need more Christmas spirit (or at least consumption).
This is why random-assignment and other research designs that more strongly identify causation are so important. And this is why we should focus on random assignment research on private and charter choice rather than the results of weaker research designs on those questions.