What are the main causes of violent crime? Culture? Racial tension? Poverty? This is the sort of question that seems irresistible as a topic for speculation: everyone has watched an episode of CSI or Law and Order, so everyone knows all about the causes of violent crime. But this is also the sort of question that social scientists have studied carefully and rigorously, using the tools of statistical analysis.
In the early 1980s, sociologists Judith and Peter Blau studied data on violent crime in the 125 largest American metropolitan areas (“The Cost of Inequality: Metropolitan Structure and Violent Crime”American Sociological Review 1982, v. 47). They found that Southern cities had higher levels of crime than did those in the North (suggesting a Southern culture of violence). Racial inequality and poverty were also positively correlated with higher levels of violent crime. Yet, when economic inequality was controlled for in the analysis, the effects of Southern culture, race, and sheer poverty disappeared. “The answer…” they concluded, “is unequivocal: income inequality in a metropolis substantially raises its rate of criminal violence.”
In 2002, researchers from the World Bank also studied the question of inequality and violent crime, this time looking at 39 different countries over more than three decades (“Inequality and Violent Crime” Journal of Law and Economics 2002, v. 45). Their conclusion? “Crime rates and inequality are positively correlated within countries and, particularly, between countries, and this correlation reflects causation from inequality to crime rates, even after controlling for other crime determinants.”
Why does economic inequality matter? Economic inequality matters because it seeds the ground for violent crime. If you want to live in a more peaceful society, create a more equal society.