IQ tests correlate with things. Thus it captures more than just how good someone is at the IQ test. You can say "There is this test, and people's scores on thi

IQ tests correlate with things. Thus it captures more than just how good someone is at the IQ test. You can say "There is this test, and people's scores on this test correlate with various things like, income, marital fidelity, religiosity, incarceration rates, job performance". We call this test the IQ test.