It breaks down the average IQ based on the number of victims, which is what you mentioned in your comment. You said that defining serial killer as having at least 2 victims is too low. But this data has the IQ averages for those who killed three or more, four or more, etc. And in all cases it shows the average as being between 90 and 100. All of this data is just basic aggregates from the Serial Killer Database (http://skdb.fgcu.edu/info.asp) by the way, if you're skeptical of the source. Is there something specific you need?
Very interesting research, thank you for linking. I only wish they'd broken out IQ by broad motive, I imagine it would differ between those doing it for "thrill/lust/power" vs "financial gain".
Aggregated data is part of the problem. And even in that small data set, the average IQ trends up as the number of victims trends up. It comes a lot closer to average IQ than the overall number of 86, but it does trend up.
The piece you linked to seems to have an explicit political agenda of disproving the popular image of a serial killer as a young white male. And that makes the entire database questionable because if that is the goal, then you explicitly define things as broadly as possible so as to accomplish your political agenda.
I'm aware there are legitimately different profiles of serial killers. For example, your typical female serial killer has murdered multiple relatives by poisoning for the insurance money. This is very different from your typical male serial killer.
At this point I am tired and frustrated and I don't know how to sort out the answer to this question. I know we have IQ scores for a number of high profile cases that clearly fit my understanding of what a serial killer is and those IQs are on the high side, fitting my general understanding. I don't know where to look for data that doesn't have a political agenda of explicitly rebutting popular perception. For the moment, I feel stymied. And the reality is this is not important enough for me to keep digging into the question indefinitely. It's already eaten an excess of my time.
>And even in that small data set, the average IQ trends up as the number of victims trends up. It comes a lot closer to average IQ than the overall number of 86, but it does trend up.
Obviously, duh. It's not because serial killers tend to be of higher IQ, but because serial killers of higher IQ can get uncaught for longer, and thus manage bigger "number of victims".