The IQ test was originally designed to determine which students in schools were likely to have problems and would benefit from extra help.
The IQ test (poorly named, I know) was remarkably effective in this. If you think about this, all of the complaints lodged against the IQ test are not problems with its original purpose. If you score low because you don't speak the language it is given in, you probably will need extra help in school. If you score low because of cultural differences, you probably will need extra help to understand things. If you score low because you can't concentrate, you probably will need extra help.
The trick is that what kind of help isn't obvious from the test. It is great as a first indicator that some sort of problem exists, and then you need to evaluate what sort of problem and what kind of help is best to provide.
It was not intended to figure out subtle degrees of intelligence. It was designed to indicate problems, and that it does. It's a shame it's gotten used for all sorts of other things in all sorts of other ways, some of them quite bad.
Discussion (3)
I don't recall the source for this quote, but I recall reading about an interview with the creator of the IQ test:
Q: What does your test measure?
A: It measures intelligence.
Q: And what is intelligence?
A: It is what my test measures.
That's fair. Although it doesn't measure "intelligence" as anyone thinks of it. I doubt though that can be an accurate quote from the original source, as it seems unlikely it'd be in English, but maybe it is. I don't know. I just know the test was designed to determine which kids would need more help in school, and it is a very good predictor of which kids will likely fall behind without intervention.
If the claim included in the description of this claim is true, then I agree.
Claims inspired by this comment
IQ tests do not always accurately measure intelligence