Measuring peacefulness according to five indicators: the number of homicides, number of violent crimes, the incarceration rate, number of police employees and the availability of small arms, the USPI indicates that, "the United States is significantly less violent and more peaceful than it used to be." However, "the U.S. remains significantly less peaceful than other advanced nations," and as Florida notes, "It is one of only two OECD nations that are not among the top 50 most peaceful nations in the world."
At the state level, the report indicates that, "New England ranks as the nation's most peaceful region with the lowest scores," with Maine declared "the most peaceful state for the 11th consecutive year." On the other end of the spectrum, "Louisiana is the least peaceful state on the State Peace Index, followed by Tennessee, Nevada, Florida, and Arizona."
This year is the first time that the study ranked the peacefulness of the 61 most populous metropolitan areas in the country, with Cambridge, MA coming out on top and Detroit on the bottom.
Florida finds correlations between violence and a number of socio-economic factors including education, religiosity, political orientation, and teen pregnancy rates.
According to Florida, "Two factors that stand out are poverty and inequality. Higher levels of violence and lower levels of peace are closely associated with both, at the state and metro levels. The report finds one of the very highest correlations between lack of peace and the percentage of children living in single parent households."