What’s the evidence for Evidence-based HR?

Whenever someone makes a claim about the positive effects of employee engagement on performance, retention and apparently everything, I can’t help but ask a simple question: What’s the evidence? Not once has anyone provided valid evidence. Even senior HR professionals come up with answers like “it’s obvious”, “you can just see it”, “I read a study once” (I happened to know the study and it isn’t actually relevant), “I heard a presentation about it”, “it was on a graph” or “there’s tonnes of evidence” (but were unable to say what any of it was). Personally, I find it shocking that any profession that wants to be taken seriously is so unconcerned and uninformed about the nature of the evidence base for what it does.

I find it shocking that any profession