I want to clarify: IQ is very useful and powerful for research purposes. It’s not nearly as interesting for you personally.
How can this be?
Consider something like income inequality: kids from rich families are at an advantage in life; kids from poor families are at a disadvantage.
From a research point of view, it’s really important to understand this is true. A scientific establishment in denial that having wealthy parents gave you a leg up in life would be an intellectual disgrace. Knowing that wealth runs in families is vital for even a minimal understanding of society, and anybody forced to deny that for political reasons would end up so hopelessly confused that they might as well just give up on having a coherent world-view.
From an personal point of view, coming from a poor family probably isn’t great but shouldn’t be infinitely discouraging. It doesn’t suggest that some kid should think to herself “I come from a family that only makes $30,000 per year, guess that means I’m doomed to be a failure forever, might as well not even try”. A poor kid is certainly at a disadvantage relative to a rich kid, but probably she knew that already long before any scientist came around to tell her. If she took the scientific study of intergenerational income transmission as something more official and final than her general sense that life was hard – if she obsessively recorded every raise and bonus her parents got on the grounds that it determined her own hope for the future – she would be giving the science more weight than it deserves.
So to the people who write me heartfelt letters complaining about their low IQs, I want to make two important points. First, we’re not that good at measuring individual IQs. Second, individual IQs aren’t that good at predicting things.
I haven’t taken an IQ test myself, and tend to agree with Scott Alexander’s Against Individual IQ Worries: