[lutusp]

> As I understand it, this article is about a controlled experiment. In which case there is no confounding and therefore correlation implies causation.

Without a testable, falsifiable theory -- an explanation, correlations don't -- can't -- imply a cause-effect relationship. Not in a scientific sense, anyway. If I say that puddles cause rain, people will laugh. But if I say I performed a controlled experiment in a very large building like the VAB at Cape Canaveral in which I produce puddles and the puddles really do cause the subsequent rain, but I omit the details (or simply don't understand my own result), I get the last laugh. It's true, but it's not science unless there's a theoretical dimension, not just a description. It's not science unless I understand my result.