IQ is a scalar. We need a vector. And....what if you don't care about taking a battery of tests? Is the test valid? And if you only pick people who do care to take the test is the test valid? Too much noise in IQ tests or even a battery of test. Language is expected to be the most correlated. It is required to comprehend the other factors. What's the trade-off between time and accuracy? Not saying we can't learn anything from IQ,  its just much less than we think.,(reply>), You can believe whatever you like but it remains the best predictor of success in life, wealth, and the ability to perform cognitively demanding tasks.