Percent Black and Crime

An interesting predictor of local crime rates is the percent of the region examined that is black. Some may point to this and say that this is a result of discrimination. This is unlikely, as Rubenstein (2016) finds “Victim and witness surveys show that police arrest violent criminals in close proportion to the rates at which criminals of different races commit violent crimes.” Other reasons could include socioeconomic standards in the neighborhood, race differences in IQ, and underlying genetic differences in crime-committing-variables (aggression, ASB, etc.). Whatever the cause, the evidence for the association is documented in this blog post.

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Response to Richardson and Norgate (2015): “Does IQ Really Predict Job Performance?”

Ken Richardson is a figure in the psychometric world who has made some pretty bold claims about g, heritability, and IQ testing as a whole. Out of his many (flawed) works, there is one in particular I wished to respond to. Richardson and Norgate (2015) argue that the correlation between IQ and job performance is, at best, greatly overestimated by the pro-IQ side (figures such as Ian Deary, Richard Haier, Arthur Jensen, and most notably in the job performance debate, Frank Schmidt and John Hunter) and at worst, entirely useless. Do their arguments hold up?

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Crime and IQ: A Review

NOTE: This article was posted on someone’s Twitter on 7/20/2020 which prompted me to correct some errors I remembered having in it. The first sentence, which the tweet quoted to my dismay, read “there is a moderate to strong relationship between criminality and intelligence.” This was a misrepresentation of the data on my part, and I changed it to what it is now (below). I also responded to some criticisms about “high IQ people just being less likely to get caught” and deleted a couple sentences.

There is a low to moderate correlation between criminality and intelligence, but the average IQ of criminals and non-criminals is large and sociologically important. The evidence for this will be documented below, though explanations for why this is will be saved for another day:

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