Occidentalist has updated his survey of surveys. Despite radical social changes and a wide variety of testing regimes, American black IQ always tests out one standard deviation below American white IQ. Similar differences in character and criminal propensities are obvious.
How big is one standard deviation? If you take a random black, and a random white, it means that someone’s race does not tell you a whole lot about which one is smarter, but, in practice, one never meets a random black and a random white.
Suppose blacks are affirmative actioned into a diverse elite group, police, academia, etc. Then, because IQ variance between random white academics is lot less than IQ variance between random whites, almost every black academic will be markedly and strikingly dumber than every white academic, meaning that few black academics (in a non elite university no black academics whatever) will be capable of doing the kind of academic things that academics traditionally do. Similarly, in a police force, all or almost all black cops will be markedly more criminal than all or almost all white cops.
This leads to the one rotten apple problem. In a diverse police force, being honest is racist and disloyal to you fellow cops. In a diverse academia, doing stuff that requires intelligence and ability is racist and anti scientific.
We see a similar result when women are affirmative actioned into jobs requiring upper body physical strength: We get the no lift rule. People, both males and females, are forbidden to use upper body strength. In hospitals, when you need a sick patient lifted up, you cannot call a male nurse, because that would be discrimination. They could not say equal pay for equal work, if some tasks were manifestly unequal. This sometimes results in patients dying. Computer science courses are dumbed down so that females can pass them. The removal of certain aspects of computer science on which men perform markedly better than women makes both male students and female students ignorant, makes them both worse off. Not only the males, but also the females would be better off covering those areas, even if the women performed poorly.
In general, whenever you mingle two groups, you get a leveling down to the worst characteristics of both groups, so that the diverse group is worse in important ways to at least one of the unmingled groups, and usually worse in important ways to both of the unmingled groups, partly because there are few groups so uniformly bad that they do not have at least some virtues, and partly because differences in virtues leads to those virtues being deprecated: The no lift rule denies both men and women the use of their upper body strength, making women effectively weaker than they already are. Similarly, in diverse communities, blacks tend to be more criminal than they already are.