How do you define 'serious scientific literature?' In other words, what type of evidence would you like me to present? Does any peer reviewed research that uses IQ as a factor count as serious? (Obviously, I won't present research that is about IQ measurement.)
I have never had IQ test taken, but countless of times BMI has been calculated. Mind you I have had other mental tests done due to ADHD and Autism concerns, and some of them were similar about abstract logic, but they were combined with other things like focus, memory, multitasking, literary understanding and other mental capabilities. The results of these tests were presented as percentiles in the population.
Interesting. I was given an IQ test for ADHD diagnostic purposes. There were other test given, as well. And in my opinion, the other tests were more indicative than the IQ test was (which I think is falling out of favor with ADHD testing). Then again, there were some issues with my test and scoring, so it makes me even more dubious of the (psuedo)science.
I went through the arduous process merely for the formal documentation, which in hindsight has served me well. Not a single doctor has ever questioned my diagnosis. However, as the psych told me, a 10 minute conversation with me should honestly have been evidence enough. ;)
Interestingly, the actual ADHD tests didn't find any issues, my main issue was my mind wandering in social situations, listening, understanding, keeping track of conversations and my own input. But whatever the tests were they were stimulating enough that I had no problem focusing. It's also repetitive, routineus actions that I have trouble focusing on, so it's almost like untestable issues. I did get the diagnosis though, I don't remember with what justification since the tests didn't allow for that.
Do you mean "why is it still used in popsci"? I'd wager because it makes people feel a similar way to other pseudo scientific categorizations, but that's mostly speculation on my part. Add in a bit of inertia and the simplicity of it ("let's reduce the cognitive ability of people across the world to a single number!") and, to me, I can see the appeal for others.
Devil's Advocate: Then why is it so heavily used still? (Then again, I guess back to my initial point -- the same could be said for BMI.)