Well you could use peer ranking, and see how well the rankings correlate with one another. That's the method they use in expertise studies for subjective fields.

I don't know. A subjective judgement of the results doesn't mean that a study isn't scientific. You just need to be systematic and to be explicit about how you measure.

I agree. You're right. You do need something.

Part of my point was, though, that nobody should need to do an objective study. :) Because it's pretty frickin obvious to anybody with a brain who works in the field, in my judgment. And it's not limited to our field. It's a human-wide phenomenon.