Imprisonment incapacitates the prisoner by physically removing them from the society against which they are deemed to have offended. Long term imprisonment with the intention to incapacitate is often used by criminal justice systems against habitual criminals who recidivate. Therefore, incapacitation focuses on removing the ability of the offenders to commit future crimes by use of imprisonment rather than focusing on rehabilitation or prevention.
In his 2004 article, Steven Levitt attributes part of the decline in the crime rate seen beginning in the mid 1990s to the inability of inmates to recidivate as sentences for crimes, especially for repeat offenders, had been greatly increased. Examples of these laws include back-to-back life sentences, three-strikes sentencing, and other habitual offender laws. In the United States, 18 U.S.C. § 3553 states that one of the purposes of criminal sentencing is to "protect the public from further crimes of the defendant." Quite simply, those incarcerated can not commit further crimes against society.
Most of the justification for the continued high levels of those in prison in the United States is due to the incapacitation effect. In the 1970s, the strong emphasis on rehabilitation that had existed since the turn of the century gave way first to a focus on equality and fairness in sentencing, and then to an increased focus on incapacitation, deterrence and restraint strategies of crime prevention.
However, the increase in the number of persons incarcerated has greatly increased due to the implementation of this concept. For the 30 years prior to 1974, the average number or persons incarcerated was 103 per 100,000. This number had climbed to 600 per 100,000 by 1995. 
The effect of incapacitation often has the unintended effect of incarceration of inmates' families 
MacKenzie found that incapacitating offenders who continue to commit crimes at high rates is effective, it works best as a part of a multi-tiered approach 
The crime rate in the United States unexpectedly fell sharply in the 1990s, in almost all demographic and geographic areas, and a portion of the drop has been attributed to the incapacitation effect. Beginning in the mid-1990s, sentences began to lengthen due to habitual felon statutes being passed in many states as well as changes in sentencing statutes which reduced the credit inmates could amass to reduce the amount of time they were held in prison.
Recidivism remains a problem in the United States, where according to a 2005 Bureau of Justice Statistics rates of recidivism average around 67.5%, although this number is heavily dependent on the type of crime when applied to specific cases. The rate of recidivism has increased since the 1990s.
However, the cost to incarcerate inmates continues to rise, which has led states to release inmates before the end of their assigned term, such as in North Carolina's advanced supervisory release program. The balance between the cost of incarceration and the reduction in crime due to the incapacitation effect remains difficult to make decisions on and problematic for politicians.
In 2015, a similar problem was noted in North Carolina, where a court-ordered reduction in student suspensions appears to be linked in an increase in on-campus crime.
A similar drop in crime was noted in Australia, where the marked increase in the prison population was termed a" very blunt instrument of crime control but it is an important instrument, nonetheless(Weatherburn, 2006)." The paper further states that achieving a 10 percent reduction in the 2006 burglary rate an increase imprisonment of 34 percent would be needed. Doing so would increase cost by an additional $26 million per year. Further research was recommended as to the cost-effectiveness of this method of controlling crime.
- Zimring, F. E., & Hawkins, Gordon. (1995). Incapacitation: penal confinement and the restraint of crime. New York: Oxford University Press.
- Bureau of Justice Statistics 1995. The nation's correctional population tops 5 million. Washington, D.C.: U.S. Department of Justice Bureau of Justice Statistics (NCJ-156432)
- Clear, T. R. (1996). The Unintended Consequences of Incarceration. Paper presented at the NIJ workshop on corrections research, Feb. 14-15
Weatherburn, Don, Jiuzhao Hua, and Steve Moffatt. "How Much Crime Does Prison Stop-The Incapacitation Effect of Prison on Burglary." IJPS 2 (2006)
- Precrime — criminal justice system approaches to crimes not yet committed
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