> I find it hard to believe that you can get actually get good data from self-reporting in surveys.

Especially when you consider the Lizardman's Constant of 4%

https://slatestarcodex.com/2013/04/12/noisy-poll-results-and...

This article was written in 2013. The Internet has become a significantly more toxic place since then, and I would imagine the constant is closer to 15-20% these days.