Well, often the data is conclusions from my decades of experience. It's not like I can show that in Wikipedia.

What I actually mostly do is saying "Doing X never works, because Y, instead I like to do Z because...", and it has reasonable success.

People want to hear it can work.

Sourcing data is expensive. I think it's best not to underestimate just how much development has to be done based upon gut feel, trust or experience simply because proving it would take too long.

If it's two people arguing their own opinions at each other and neither one has relevant data where exactly do you go from there? The one with 2 years experience or the one with 15?

Sometimes the data is the experience, and it's hard to dump your personal experience on someone and make them ingest it. Sometimes you've tried approach X a couple of times and it always failed, but you don't have a scientific proof it will fail again. You just know from experience if you do X it usually ends up in tears and all-nighters and missed deadlines. Not because you have an Excel table proving it, but because you've lived it.