One of the twenty or so books that I am ploughing my way through right now is ‘Hard Facts, Dangerous Half-Truths & Total Nonsense‘. It is all about how evidence-based management can actually help you improve the way that you manage today. In there, I read the frankly gobsmacking news that IQ was the best predictor of job performance. Gobsmacking because I have had a long love-hate affair with IQ and finally turned myself over to the dark side by trying to understand and leverage Gardner’s theory of multiple intelligences.
When I was in my early teens, my idea of fun was doing taking self-tests for IQ (which only begins to tell you the kind of childhood I had). This is the bad old-fashioned IQ that everyone loves to hate these days focussing almost solely on linguistic and logico-mathematical intelligence. I learnt quickly what many found out before me: it is pretty simple to learn how to improve your scores on these types of test. Mine were high and only got higher. It only helped that my greatest strengths were reading, numbers & arithmetic patterns. Later, when I did training with a group of leaders from Razorfish, I found that there were plenty of other people who much more advanced in emotional intelligences. We learned there (and I read in subsequent books such as this or this) that these other intelligences were much more potent. So how come that linguistic and logico-mathematical intelligences win out in being good at your job?
The answer — and why Pfeffer and Sutton call it a ‘half’-truth — seems to be just how good a predictor IQ actually is. It typical correlates less than 40% with job performance, i.e. 84% of job performance is not caused by IQ. What is jaw dropping here is that this is the best predictor of job performance of which we know, i.e. it is very hard to predict job performance at all.