+1 for the Metaculus [1] reference. I came across the concept of calibration while reading “How to measure anything” (see the _equivalent bet test_ in this review [2]) and find it really powerful in theory and really hard in practice.

[1] https://www.metaculus.com/home/

[2] https://www.lesswrong.com/posts/ybYBCK9D7MZCcdArB/how-to-mea...