Why is IQ useful? Why does it represent more than just a score on a test? Because it correlates quite well with certain aspects of life, mostly academic (GPA etc) and financial (income etc), as well as being reasonably effective in testing for retardation. If IQ didn't correlate so well with any of these things, then it would be less relevant as a statistic. Given that the correlation of IQ with academic performance and career success is far worse towards the higher end, it is not really worth noting or comparing your scores so long as they are around 2SD or higher.