Using CIA data on race (admittedly crude), I calculated the Pearson correlation between percent black and national homicide rates. For 180 countries, it is .50--a strong association. More blacks means more homicide. Percent black is as predictive as mean IQ or the GINI measure of income inequality. While we're at it, the black-inequality correlation is .45. Bigger gaps between the wealthy and the poor go hand in hand with more blacks.