What is with that automatic assumption on HN that whatever scientific paper is under discussion, they surely did ignored <insert completely obvious possibility that they actually did dealt with>?
I'm being equivocal in my wording, because that's what you do when you're being polite, and you're giving the authors the benefit of the doubt. Maybe I missed something, but I didn't see them control for this in a way that satisfies me that the issue was addressed.
