An IQ test can be used during the hiring process but the employer has to be able to defend its use as directly relevant to the work at hand. So most employers aren't willing to spend the legal fees related to defending the use of a direct IQ test... Possibly because the college degree is a good enough litmus test for IQ to satisfy their needs.
It’s not difficult to demonstrate that IQ is relevant to job performance (its the best predictor of performance for most jobs). The problem is to demonstrate that it doesn’t have a discriminatory effect (there are large, persistent differences in IQ between races).
