You're simply wrong. It's not a data set size issue. The issue is that most businesses can't show a sufficient connection between an IQ test and the responsibil

You're simply wrong. It's not a data set size issue. The issue is that most businesses can't show a sufficient connection between an IQ test and the responsibilities of a job to establish a business necessity for having the IQ test. If they can show a business necessity, they don't need to show that the IQ test actually predicts job performance. Notably, the army's test is not an IQ test. It is an aptitude test which is a very different thing. An aptitude test specific things are that directly and strongly related to the job (or jobs) for which the applicant is applying.