Youthful Exuberance

Between 1978 and 1993, the rate at which adults were arrested for murder declined by about 7 percent, while the rate for juveniles skyrocketed by 177 percent. Some prominent criminologists, such as John DiIulio and James Q. Wilson, believe the huge increase among juvenile criminals reflects the rise of "super-predators," a new breed of sociopathic kids who are qualitatively different from past generations of offenders.

In "Juvenile Crime and Punishment," a recent National Bureau of Economic Research working paper, Harvard University's Steven D. Levitt suggests an alternative explanation for the boom in adolescent anarchy: It reflects "a rational…response to a change in the relative incentives for juveniles and adults to engage in criminal activities." Levitt notes that over the past two decades the adult prison population tripled, while juvenile lock-ups failed to keep pace. Since kids were more likely to get away with crime, he suggests, they were more likely to engage in it.

Levitt calculates that the ratio of adult state and federal prisoners to violent crimes committed by adults, a "rough proxy" for the severity of the criminal justice system, rose from 0.34 to 0.55, an increase of over 60 percent, from 1978 to 1993. The corresponding ratio for young offenders, however, declined from 0.36 to 0.29. Juvenile punishments, concludes Levitt, "were comparable to adult punishments in 1978, but were only about half as severe in 1993."

Levitt notes that in states where adult offenders are much more likely to be imprisoned than juveniles, violent crime rates drop by 25 percent when a cohort becomes a legal adult. Far from indicating a new breed of "super-predator," such findings suggest that young criminals–like their older counterparts–can be deterred by the threat of doing time.