So incarceration skyrocketed and crime was in free fall. But conflating simple correlation with causation in this case is a costly mistake. A report from the Brennan Center for Justice at NYU School of Law, called What Caused the Crime Decline? finds that increasing incarceration is not the answer. As Nobel laureate economist Joseph Stiglitz writes in the foreword, “This prodigious rate of incarceration is not only inhumane, it is economic folly.”
Our team of economic and criminal justice researchers spent the last 20 months testing fourteen popular theories for the crime decline. We delved deep into over 30 years of data collected from all 50 states and the 50 largest cities. The results are sharply etched: We do not know with precision what caused the crime decline, but the growth in incarceration played only a minor role, and now has a negligible impact.
...We find that this growth in incarceration was responsible for approximately 5 percent of the drop in crime in the 1990s. (This could vary from 0 to 10 percent.) Since then, however, increases in incarceration have had essentially zero effect on crime. The positive returns are gone. That means the colossal number of Americans cycling in and out of prisons and jails over the last 13 years was not responsible for any meaningful fraction of the drop in crime.
...Incarceration is not just any government policy. Mass incarceration comes at an incredible cost. "A year in prison can cost more than a year at Harvard," Stiglitz points out. Taxpayers spend $260 billion a year on criminal justice. And there will continue to be less and less to show for it, as more people are incarcerated.
There are significant human costs as well—to individuals, families, communities, and the country. Spending a dollar on prisons is not the same as spending it on public television or the military. Prisons result in an enormous waste of human capital. Instead of so many low-level offenders languishing behind bars, they could be earning wages and contributing to the economy. Incarceration is so concentrated in certain communities that it has disrupted the gender balance and marriage rates. The costs are intergenerational. There are 2.7 million minor children with a parent behind bars. More than 1 in 9 black children have a parent incarcerated.
Research also shows that incarceration can actually increase future crime. Criminologists call this the “criminogenic effect” of prison. It is particularly powerful on low-level offenders. Once individuals enter prison, they are surrounded by other prisoners who have often committed more serious and violent offenses. Prison conditions also breed violent and anti-social behavior. Former prisoners often have trouble finding employment and reintegrating into society due to legal barriers, social stigma, and psychological scarring from prison. Approximately 600,000 prisoners reenter society each year. Those who can find employment earn 40 percent less than their peers, and 60 percent face long-term unemployment. Researchers estimate that the country’s poverty rate would have been more than 20 percent lower between 1980 and 2004 without mass incarceration.
