You state that as obvious, but I'm not sure -- that is an interesting question that bears some examination. https://en.wikipedia.org/wiki/Statistical_correlati

You state that as obvious, but I'm not sure -- that is an interesting question that bears some examination. https://en.wikipedia.org/wiki/Statistical_correlations_of_criminal_behaviour https://en.wikipedia.org/wiki/Statistical_correlations_of_cr... doesn't seem to answer directly, but does talk about some genetic and environmental causes for violent crime. It seems likely that there are some factors contributing to the US's higher murder rate that would also be expected to spill over into the violent crime rate. I'd like to dig into whether the US has higher non-violent crime rates than other countries as well, but can't find any good summaries right now. So I think I'd expect to see a lot more violent crime if you increased the murder rate by 6.5x, and that might get you close to 6.5x the prison population depending on the breakdown of the difference in crime rates. But having said that, it seems likely that there are a few factors contributing to the incarceration rate, not just the higher base rate of violent crime.