However the measure that they hit on is actually a reasonable way of improving your interview process. There is general research to that end, and it was presented in that case. But the sample set of previous employees hired by Duke Power Co was not large enough to statistically demonstrate that fact. Therefore the court decided as it did. As a result the fact that IQ tests are more effective at figuring out who to hire than human interviews is no longer actionable by any normal employer.
There are some notable exceptions. For example the US military has enough history and experience with the ASVAB that they are able to safely use it. But very few companies are in a position to do such research for themselves.
If it can be established as a fact, its actionable. It can't be assumed to be a fact for the specific jobs it is applied to, however -- and while Griggs may be a leading case, that's pretty clearly the intent of the burden established by the Civil Rights Act for the employer in disparate impact situations.
> But very few companies are in a position to do such research for themselves.
Any company is in the position to do it (or pay to have it done), for very few companies is the expected benefit justify the cost, because the expected utility of general intelligence testing, even where any such benefit is rationally expected to be born out, is pretty low compared to more specific job-focused alternatives that are also easier to demonstrate are job related if they have a disparate impact.
Wrong.
In order to be in a position to do it, you need to start with a sample of many thousands of people being hired into a specific kind of job, all of whom have been given the test in question, and all of whom are then judged by standardized metrics. ONLY THEN can you collect enough data to make strong statistical inferences on this issue.
The military can meet this threshold. Very, very few private employers can. And claiming otherwise is wrong.
...the expected utility of general intelligence testing, even where any such benefit is rationally expected to be born out, is pretty low compared to more specific job-focused alternatives that are also easier to demonstrate are job related if they have a disparate impact.
I do not believe this to be the case for most entry-level jobs. Can you cite specific research indicating otherwise?
Perhaps you should read Griggs v. Duke Power Co., 401 U.S. 424 (1971), particularly at 436: "Nothing in the Act precludes the use of testing or measuring procedures; obviously they are useful. What Congress has forbidden is giving these devices and mechanisms controlling force unless they are demonstrably a reasonable measure of job performance."
The Supreme Court has not, contrary to your description, "ruled that it is illegal to make an IQ test be part of a job hiring practice because allowing it will discriminate against blacks", it has ruled that it is illegal to make an IQ test be part of job hiring where the IQ test is not demonstrably a reasonable measure of job performance, given that blacks scored lower on the tests, under the Civil Rights Act of 1964 which prohibited deliberate discrimination based on race, and placed the burden on employers to demonstrated that selective measures with discriminatory effect were reasonably directed at job requirements.
IOW, it is not that blacks do worse on the test, on average, that makes it illegal, but that fact combined with a situation where the employer cannot demonstrated that it is reasonably related to the job function.
(Its perhaps worth noting that the specific requirement at issue in the case went into effect on the day the Civil Rights Act of 1964 went into effect, the same day that the overt policy of racial discrimination that it replaced was discontinued.)