Normal people’s IQ is between 90 and 109; 110 to 119 is an above-average level; 120 to 139 is an excellent level; and above 140 is a very excellent level. But the idea that IQ tests alone can measure intelligence is wrong, the largest-ever study of human intelligence has found. IQ tests are fundamentally flawed because they do not take into account the complex nature and different components of human intelligence.