I saw this headline: "Billionaires are smarter, study says" and I knew I was about to read something stupid

I was not disappointed. This is how they decided that billionaires are smarter:  "He found that billionaires are, as a group, very highly educated and have high cognitive abilities. About a third of the world's billionaires attended elite schools worldwide. "  This is like saying that billionaires are smarter because they came from more affluent homes.