In the words of Michel Foucault, a French intellectual, prison is “but a recruitment center for the army of crime.” In a time when citizens are increasingly questioning the effectiveness of the criminal justice system and recidivism rates are on the rise, it is necessary to question the effectiveness of imprisonment in mitigating crime. Whether incarceration is successful in eradicating crime thus rests on whether it successfully reforms criminals and whether the act of imprisonment promotes crime in communities in the long term. With these criteria in mind, it can be argued that prisons are only effective in addressing the problem of crime if prison sentences are able to address the root causes of the crime, if resources are diverted to rehabilitation, if prisons maintain a small critical size to prevent the growth of criminal networks, and if prisons are able to mitigate the impact that mass incarceration has on communities. 


Prisons are only able to effectively reform criminals and lower the rates of recidivism if the prison sentence is able to address the root causes of the crime. At first glance, it appears that prisons have failed to prevent convicts from reoffending. According to the National Institute of Justice, about 68 percent of prisoners released in the United States were arrested for a new felony within 3 years, and 77 percent were arrested within 5 years. However, a detailed breakdown of recidivism rates reveals that imprisonment can be effective in rehabilitating criminals, but only if the prison sentence was commensurate to the nature of the crime. Sex offenders and domestic abusers tend to benefit the most from short-term prison sentences, which act to ‘convince the offender that unlawful conduct has serious consequences’. Sex offenders have a recidivism rate of 28.4 percent in the United States, as compared to a 62.7 percent recidivism rate for drug offenders, for instance. The disparity in effectiveness can be attributed to the nature of the crimes – jail time is able to dissuade sex offenders from reoffending, but is unable to address more pernicious problems like drug addiction, or unaddressed economic needs which push people into drug peddling, for example. 


When prisons focus on rehabilitation, however, they are seen to be more effective in reducing the re-offense rate, regardless of the nature of the crime. After the Singapore Prison Service introduced the Rehabilitation Framework and the Level of Service Inventory-Revised instrument to match inmates to correctional programmes based on their rehabilitation needs and criminogenic risks, as well as established a Prison School in 2000, Singapore’s recidivism rate dipped from 44.4 percent for the 1998 release cohort to 27.3 percent for the 2008 release cohort. In contrast, the American criminal justice system is characterised by a ‘for-profit’ prison system which limits inmates’ access to education and nutrition, and therefore unsurprisingly boasts the highest reoffense rate in the world at 76 percent. Evidently, prisons are only effective in reforming their inmates if efforts go towards rehabilitative rather than retributive justice. 


Additionally, if prisons are able to reduce recidivism and control the size of prison populations, they are likely to be more successful in preventing the growth of criminal networks based in prisons. Prison gangs and criminal networks often arise as a rational response to poor conditions within burdened prison systems – the Californian prison system has about 160,000 inmates, and on average holds a few thousand in each prison. In such a system, there is a large black market for illicit goods, and understaffed prison administrations are unable to provide law and order. This creates the conditions for the growth of prison gangs like the notorious Mexican Mafia, which control life both inside and outside these prisons. In contrast, the Scandinavian prison systems minimize the number of inmates held in each facility, and have reported lower occurrences of criminal organisations fomenting within prisons. 


At the same time, it must be noted that incarceration often drastically changes communities in ways which might foment crime in the long-term. Prisons will only be effective in preventing crime if they cooperate with external agencies to address the effects of imprisonment on the community. Studies have shown that the children of incarcerated parents tend to move frequently, face financial problems from a young age, struggle with emotional and family instability. Communities with high levels of mass incarceration tend to perpetuate that cycle since incarceration disrupts important social and family structures and roles. Partners which provide support services, such as the Kids in Play programme run by the Salvation Army in Singapore, are able to mitigate these impacts and break the cycle of violence and crime. 


In conclusion, prisons are only effective in combating crime if they are able to address the root causes of crime, if sufficient resources are diverted to counselling convicts and preparing them for a life outside prison, and if they are able to prevent the agglomeration of criminal networks. This is because their effectiveness should be evaluated in terms of whether they are able to prevent crime from occurring in the long-term. With the right support for criminals who have demonstrated the ability to turn over a new leaf, prisons will be able to prevent crime for good, as criminals are often pushed to reoffend if they are unable to meet their social or economic needs after leaving prison. This often has a positive impact on communities, who may be left with a ‘social vacuum’ if convicts are not rehabilitated and the impact of mass incarceration is not mitigated. If prisons are able to prevent the growth of criminal networks, they will be better able to prevent the vicious cycle of crime from perpetuating itself.