The Crud Factor: what’s the average correlation between totally random human traits?

January 24, 2025

We gathered >1 million human correlations spanning personality, demographics, behaviors, and beliefs, which enabled us to investigate an interesting question: is everything correlated with everything? In other words, is the so-called "crud factor" real? Here's our answer. On average, there is almost no correlation between human variables (see image). The average is only r=0.02, with the median even smaller at r=0.01. But this is misleading because it allows positive correlations to be cancel...

Demystifying p-values

December 31, 2022

There is a tremendous amount of confusion around what a p-value actually is, despite their widespread use in science. Here is my attempt to explain the concept of p-values concisely and clearly (including why they are useful and what often goes wrong with them). — What's a p-value? — If you run a study, then (all else equal, aside from rare edge cases) the lower the p-value, the lower the chance that your results are due to random chance or luck. More precisely: a p-value is the probab...