There's No Evidence Like No Evidence
By Bryan Caplan
Here‘s an especially wise observation by David Balan:
So then I asked him whether by “no evidence” he meant that there have been lots of studies directly on this point which came back with the result that more chemo doesn’t help, or whether he meant that there was no evidence because there were few or no relevant studies. If the former was true, then it’d be pretty much game over: the case for discontinuing the chemo would be overwhelming. But if the latter was true, then things would be much hazier: in the absence of conclusive evidence one way or the other, one would have to operate in the realm of interpreting imperfect evidence; one would have to make judgments based on anecdotal evidence, by theoretical knowledge of how the body works and how cancer works, or whatever. And good people, maybe I’m being unfair and underestimating this guy, but I swear to you that this fancy oncologist in this very prestigious institution didn’t seem to understand the difference between these two types of “no evidence.”
And in my experience, most anti-theoretical empirical economists – most notably in labor econ – don’t understand the difference either.