There are clear measurements of various abilities, but there is no measure of general intelligence in the sense of being able to process new information and draw novel conclusions about it, or think outside of existing socially dominant schemas.

Even the most ‘smart’ people I know, very few exercise this ability, even if they have it. To think well you often have to be trained to do so, and even then a lot of people will fail in that training willfully. Mostly because they are aware taht exhibiting thoughtful individuality will get them socially and career shitcanned, because so much of society is and career success is built on being a yes man.