The Institute for Economics and Peace compiled a peace index ranking the 50 states (see the map here) earlier this year. The index uses five indicators in making the peace score calculations--homicide rates, violent crime rates, incarceration rates, per capita police officers, and the availability of small arms.
At first blush, the last indicator seems to reveal an unsatisfying leftist outlook in the report as less densely populated, politically conservative flyover states tend to have less restrictive legal gun ownership requirements than Northeastern and West Coast states do. That's probably a more-or-less accurate read into the authors of the report. However, gun ownership rates are estimated rather bizarrely by the percentage of suicides in each state committed by the use of a firearm, so while this is surely influenced in some degree by the availability of guns, it's difficult to dispute that a relatively high percentage of people ending their lives by blowing their brains out instead of overdosing on sleeping pills proxies for the violent tendencies of the residents in question reasonably well. Anyway, this factor was assigned the least weight of the five, representing only 1/15th of the peace index total.
Using incarceration rates and the number of police officers per capita is a bit problematic as well. Throwing increasing numbers of people who commit crimes in prison and holding them there is arguably one of the primary reasons criminal activity has decreased in the US over the last couple of decades. Similarly, relatively large police forces could be seen as a necessary response to a violent population, but could also be viewed as an expression--not necessarily related to the actual prevalence of violence--of how high a priority that population makes deterring crime and capturing criminals.
A few years ago, I computed a strictness index that ranked states by how many people they incarcerated relative to the amount of crime that occurred. South Dakota comes out as the most 'draconian'. This is notable because the report contains a "case study" on New York and South Dakota, the former being the state where the peace index has increased the most over the last 20 years and the latter being the state where it has decreased the most over the same period of time. Singling out South Dakota as a state that has slid backwards since 1991 highlights why incarceration rates and police presence are suboptimal measures of peacefulness--homicide and other violent crime rates are almost exactly where were 20 years ago, but because the incarceration rate and the per capita police presence have both increased markedly over that period of time, South Dakota looks bad. As a law-abiding citizen, if more thugs are in jail and more patrol cars are out than they were when I was a kid, but the frequency of crime has been held in check, I'm not complaining too much. These changes are certainly preferable to even a modest uptick in the crime rate.
These qualifications notwithstanding, state-level correlations with indices like these are rarely uninteresting. So without further ado, here are some of them. Positive correlations indicate the variable in question is associated with more peace, negative correlations with less of it:
Mean IQ -- +.62
McCain's share of the '08 vote -- (.31)
McCain's share of the '08 white vote -- (.58)
Median age -- +.28*
White population % -- +.48
Black population % -- (.56)
Hispanic population % -- (.34)
NAM population % -- (.67)
Male:female sex ratio -- +.26*
* Not statistically significant at 95% confidence
The only surprise is in the sex ratio, with relatively more men being modestly correlated with more, not less, tranquility. Crime is a young person's game, so it's hardly shocking that states like Maine and Vermont, where the median age is over 40, are among the nation's least violent.
As always, higher IQ is positively associated with a higher quality of life. And also as always, ugly a fact as it is, the more black and Hispanic a place is, the lower that place's quality of life tends to be.
Although the report, at 52 pages in length, delves deep in discussing the results and implications of the index, and the racial composition of a state is apparently the single most determinative factor in how that state fares, there is not a single mention of race in the entire thing. Those of us interested in human biodiversity are often accused of being obsessed with racial differences. Well, race matters. It matter a lot. Reports like this, in which the most influential variable is inexplicably ignored, illustrate that rather than HBDers being excessively focused on race, the majority of people are tragically ignorant of it (or at least profess to be so) whenever paying attention risks casting non-whites in a bad light.
It's plausible to think that in places where crime is an acute problem, whites react by tending towards political candidates, generally Republican, who take a tough-on-crime approach, and that is reflected in the strong inverse correlation between peace and the percentage of whites who voted for McCain. Whites in the South vote heavily Republican--at rates in Alabama and Mississippi that nearly mirror black support everywhere else for whoever the Democratic candidate is--and the South, unsurprisingly, is rated the least peaceful in the country.