Income inequality and homicide rates in Canada and the United States

Previous research showing that income inequality (assessed by the Gini index) is a predictor, and hence a possible determinant, of homicide rates, whether at the cross-national, state, or city level, has been inconclusive because of a negative relationship between economic inequity and average income. Comparison across the Canadian provinces provides a test case in which average income and the Gini are, instead, positively correlated, and we find that the positive relationship between the Gini and the homicide rate is undiminished. Temporal change in the Gini is also shown to be a significant predictor of temporal change in provincial homicide rates. When Canadian provinces and U.S. states are considered together, local levels of income inequality appear to be sufficient to account for the two countries' radically different national homicide rates.