infectious diseases: it did not go up steadily, but zoomed up in a dramatic way and then suddenly dropped. Accounting for this pattern with social demographics is difficult for the simple reason that they did not change so fast or in the same way that the levels of youth violence did. Social conditions may have been setting the stage for the epidemic and channeling its location, but the particular ferocity of the epidemic could not be explained simply by structural characteristics.
Some criminologists argue that the increase in youth homicide in the 1990s was due to increasing propensities for offending in each age cohort and a demographic increase in the number of adolescents (DiIulio, 1995; Fox, 1996; Wilson, 1995). However, Cook and Laub (1998) showed that there was not an increasing propensity for violence among youth because the increase in rates of offending occurred in all cohorts, not just one, and in 1985 the rates of offending and victimization within these same cohorts were historically unremarkable. So it could not be that the violence was caused by the sudden appearance of a new, particularly violent group of young “predators” who differed from their older brothers. Their older brothers changed, too.
To explain what occurred, analysts turned to explanations that give a prominent role to a set of factors that would be considered microsocial processes, to situational factors, and to the kind of fast-moving cultural trends that are associated with fads. Blumstein (1995) hypothesized that the increase in youth homicide was a result of the nature of the crack cocaine markets. The low price of crack increased the number of transactions, creating a need for drug sellers to recruit a large number of new sellers. The resultant recruitment of adolescents into the drug market led young people to arm themselves for protection, which in turn caused violent encounters to become more deadly.
In a later study, Blumstein and Rosenfeld (1998) argued that the subsequent decrease in youth homicide could be due to increased stability in the crack market. The number of new crack users diminished, and those involved in the drug trade had the opportunity to develop dispute-resolution mechanisms other than violence. As a result, the need to keep recruiting youth as sellers abated, fewer territorial disputes erupted, and the need for youths to carry guns for protection decreased. In addition to changes in the drug markets, Blumstein and Rosenfeld (1998) identified other factors that could have contributed to the decline in youth homicide: economic expansion that created more opportunities for legitimate jobs, and police and community efforts to limit opportunities for the drug trade, remove guns from kids, and reduce conflicts among youth.
If the cocaine epidemic explains the inner-city epidemic of lethal youth violence, then one would have to conclude that the rural and suburban epidemics were of a different kind, for there is no evidence that the