IQ is hard to test (simplified tests like Raven matrices are easy to cheat, and full tests like WAIS take several days, and depend on certified professionals). Educational level is easier to evaluate (just ask for school transcripts) and correlates strongly with IQ.
Also, high IQ with low education is undesirable, because that's how you create disgruntled and unemployable people. So IQ should not be evaluated alone, but in the context of education and employability.
