This article makes such an important point and the flossing example is a perfect example to use because it is less politically and ideologically triggering than topics like education. Flossing and the Art of Scientific Investigation
One of the key ideas is captured in the following:
“… the kind of long-term randomized controlled trial needed to properly evaluate flossing is hardly, if ever, conducted — because such studies are hard to implement … Yet the notion has taken hold that expertise is fatally subjective and that only randomized controlled trials provide real knowledge. Distrusting expertise makes it easy to confuse an absence of randomized evaluations with an absence of knowledge. And this leads to the false belief that knowledge of what works in social policy, education or fighting terrorism can come only from randomized evaluations. But by that logic (as a spoof scientific article claimed), we don’t know if parachutes really work because we have no randomized controlled trials of them.”
I’ve written on this topic before but it’s worth coming back to. Education reform advocates have become infatuated with the idea of “evidence-based” interventions and for too many of them “evidence” is synonymous with some type of experimental evaluation. Funny enough, their evaluation dollars don’t flow towards longitudinal, mixed-method evaluations, but rather to short-term quantitative evaluations that rely on easy-to-measure and short-term metrics like test scores. Combine that with rhetoric and policy stances that undermine the value of expertise (something that, by definition, is developed over years of learning and practice and is lost when teachers exit the profession within 5-7 years) and you have a recipe for shallow, ultimately ineffective policy changes.