That is a new paper by Jonathan Wai, from the latest issue of Intelligence, with the subtitle “Cognitive ability, education, and sex differences,” and here is the abstract:
Are the American elite drawn from the cognitive elite? To address this, five groups of America’s elite (total N = 2254) were examined: Fortune 500 CEOs, federal judges, billionaires, Senators, and members of the House of Representatives. Within each of these groups, nearly all had attended college with the majority having attended either a highly selective undergraduate institution or graduate school of some kind. High average test scores required for admission to these institutions indicated those who rise to or are selected for these positions are highly filtered for ability. Ability and education level differences were found across various sectors in which the billionaires earned their wealth (e.g., technology vs. fashion and retail); even within billionaires and CEOs wealth was found to be connected to ability and education. Within the Senate and House, Democrats had a higher level of ability and education than Republicans. Females were underrepresented among all groups, but to a lesser degree among federal judges and Democrats and to a larger degree among Republicans and CEOs. America’s elite are largely drawn from the intellectually gifted, with many in the top 1% of ability.
I don’t yet see this paper on-line, but here is some summary coverage.