Viewpoints: Now, California decides: Who stays, goes in prisons?

The U.S. Supreme Court has ordered California to reduce its prison population by more than 20 percent. The fiscal crisis is impelling states, without court order, to reconsider the four-decade-long increase in prison and jail populations that has resulted in the incarceration of 1 percent of our nation's adult population. In his dissent, Justice Samuel Alito ominously warned that "today's decision, like prior prisoner release orders, will lead to a grim roster of victims." Whether Justice Alito is prophetic will depend a lot on how California and other states contemplating sharp reductions in prison populations go about doing it.

Our nation's prisons confine some very dangerous people. They also house people who do not pose a risk to public safety. There is no foolproof way of distinguishing between these two types, but there are ways that we know don't work.

One is distinguishing inmates by the type of offense for which they were incarcerated. Public officials try to calm public fears about early release or diversion programs by saying that they apply only to "nonviolent" offenders. A U.S. Bureau of Justice statistics study by Patrick Langen and David Levin demonstrates that conviction for a violent offense does not predict recidivism. Indeed, the three-year rearrest rate for released prisoners who had been convicted of a violent crime was lower, not higher, than that for those who had been convicted of a property crime, 61.7 percent vs. 73.8 percent.

Is there any good basis for predicting who will be the most dangerous criminals if they are released from prison or diverted in the first place? No method is perfect, but Richard Berk, a professor at the University of Pennsylvania, has been a pioneer in developing prediction methods that can greatly reduce the risk of the release or non-incarceration of dangerous offenders. One of the key predictors in his model is age – older offenders are far less likely to recidivate than younger offenders. The Langen and Levin study finds that the three-year rearrest rate of released prisoners who were 45 or older was 40 percent lower than the rate for those who were 18 to 24 at release.

Justice Alito's justifiable concerns about public safety can also be addressed by intensive monitoring of the higher risk individuals who are paroled or diverted. This may require states to invest more in probation and parole monitoring, even as they are cutting back on prisons, but the return in terms of improved public safety will likely make this a sound investment.

The work on dangerousness prediction lays bare a fundamental conundrum for our nation's crime control policy: Should prison release decisions be based primarily on what people did or what they may do if released? According to the California Department of Corrections and Rehabilitation, 15 percent of its prison population is 50 or older. Most of California's elderly prisoners are there because they committed very serious crimes like murder or were sentenced under the state's "three-strikes" law, yet, as a group, these individuals are also the least dangerous inmates.

There is no easy way out of resolving this conundrum, but it must be confronted. There are, however, ways of avoiding it in the future. Dan Nagin recently authored an essay with Steven Durlauf of the University of Wisconsin titled "Imprisonment and Crime: Can Both Be Reduced?" The essay argues that there is no good evidence that lengthy prison sentences like those required by California's "three-strikes" law deter crime. However, there is very good evidence that the police, if properly deployed, are very effective in deterring crime.

This conclusion is important to devising more sensible and efficient crime control policies for the future because crime control by incapacitation necessarily involves balancing the trade-off between higher crime rates and lower imprisonment rates. By contrast, if the police are effective in deterring crime from happening in the first place, we can have both less crime and less imprisonment – if a crime doesn't happen, there is no one to be punished.

Thus, we argue that reductions in prison population can be achieved without jeopardizing public safety. This, however, will require the adoption of innovative methods for identifying and controlling the highest risk offenders and the strategic use of the police, rather than lengthy prison sentences, to deter crime and thereby avert the need for punishment.