And yet all kinds of claims are made on Hacker News, like how to be an entrepreneur or the best way to run a start-up, and no-one ever asks for the data. It seems like this demand for data is highly selective and used to justify the lazy attitude toward UX that plagues the majority of software. It's a dodge that I see all the time - a UX person proposes some improvement, a developer says "Well I don't think that's a good user experience, we should really A/B test it, oh wait, we don't have the time for that right now, that's too bad..." And the proposed improvement is something totally obvious, like the one in this article: buttons should have accurate, non-generic labels. You have to wonder if someone who disagree with something that obvious is arguing in good faith, or just doesn't like being told what to do.