Incapacitation as a Strategy for Crime Control: Possibilities and Pitfalls

A number of estimates of incapacitative effects from incarceration of convicted offenders are available. While these estimates vary in absolute magnitude, the studies consistently find that crime reduction achieved by existing collective incapacitation policies is modest, at under 20 percent of crimes prevented. Further crime reduction from alternative policies that would impose fairly stringent mandatory five-year prison terms after convictions for serious offenses is similarly modest. Implementing these alternative policies, however, would result in dramatic increases in already record-size prison populations. In view of the limited crime reduction and enormous increases in prison population associated with collective incapacitation policies, recent research has explored the potential benefits of more selective or targeted incapacitation. If a small number of high-rate offenders commit a disproportionately large amount of crime, targeting limited prison resources on these offenders should achieve increased crime control without increasing prison populations unreasonably. Such a policy depends on identifying high-rate offenders prospectively, and early in their careers. Recent efforts to use predictions of individual crime rates as a basis for selective incapacitation are plagued by ethical and empirical problems. An alternative approach relies on observed differences in the criminal career patterns of offenders charged with different offenses to identify offenses committed by offenders who on the average commit crimes at higher rates and have longer careers. This approach may achieve differential incapacitation effects while avoiding many of the ethical and empirical problems posed by sentencing policies that employ individual-level predictions to distinguish among offenders.