Punishment aside, we need to focus much more on crime prevention 

Americans tend to associate “crime prevention” with Democrats and “accountability for criminals” with Republicans.

Democrats want government to invest in crime prevention because they’re worried we have too many people behind bars; Republicans should also be lining up behind that idea, but for the exact opposite reason: It will never be possible to put enough people behind bars to solve the crime problem. Impunity for most crimes is inevitable.  

This is not a political or ideological argument. Nor is it about the underlying causes of crime, or your view of human nature, or what you believe is the right punishment or moral response for different crimes. This is just about math. 

Imagine that you, dear reader, were — God forbid — held up and robbed at gun point. What are the chances the person who robs you will wind up serving any time in prison? 

Today, only about half of the robberies that take place are even reported to the police, according to crime victimization surveys. Of robberies reported, only about one-third result in arrest, and about one-fifth result in some prison time. This implies that just three out of 100 robbery offenders wind up in prison.

And I'm not cherry-picking the robbery data, either. I did not. The figures are around 1 percent for burglaries, 1 percent for motor vehicle theft (harmful to low-income victims and the source of many cars used in other crimes such as drive-by shootings and gun robberies), and 2 percent for rapes and sexual assaults. Even for murder, the share who actually do time is still just 38 percent.

I understand that there may be a directional debate within America about these numbers. Prison abolitionists will even argue they should be lower. I imagine everyone else will be shocked that the numbers are so low and wish they were higher. But the key point is that the math just doesn’t work for trying to “solve” crime through imprisonment alone. The math suggests that even a doubling of law enforcement, criminal courts, and prison beds, at a cost of billions of dollars, would still result in prison time for six out of 100 robberies.

We might be able to increase that number a bit further by focusing on giving more short sentences and fewer long ones, but there’s only so far that will take us, given the public’s view that most prison sentences are currently about right — or if anything too short. Even tripling the prison population, as unimaginable as that might be, wouldn’t much change the basic math here. 

But wait, you might say — we must recognize that prison doesn’t just incapacitate offenders, it also deters crime. One goal of prisons may be to prevent crime from occurring in the first place.  

Once we recognize that deterrence is a key (if not the key) way prison affects crime, we’ve gotten ourselves on the right path to a more viable solution. We need both the left and right to start asking the same question: What is the best way to prevent crime? Once everyone is on “team crime prevention,” we can all look at the same data together to figure out what prevents the most crimes possible at the lowest possible cost to society: prisons or something else? 

My math is a version of a calculation carried out in 1975 by Harvard Professor James Q. Wilson, then one of the nation’s leading crime experts. He, too, could see the daunting prison math. He nevertheless pushed for more prisons, partly because, at the time, social scientists thought prevention wasn’t possible through non-prison means. But we have learned a lot since then.  

Stanford law Professor John Donohue argues that current evidence shows early childhood education prevents more crime per dollar than prison does. The same seems to be true for behavioral economics programs that help teens and young adults to avoid engaging in impulsive violence; changes in urban planning that get us more “eyes on the street”; and hiring more police and nonprofit “violence interrupters,” targeting where they work using predictive models of crime patterns. 

Prevention, besides its potential for effectiveness, should hold bipartisan appeal. It gets us out of our usual partisan fights about the right punishment after a crime has happened — with effective prevention, there’s no crime victim in the first place. 

With respect to crime and violence in America: Impunity is inevitable, but thankfully, prevention is possible.  

Jens Ludwig is the Edwin A. and Betty L. Bergman Distinguished Service Professor at the University of Chicago, Pritzker Director of the University of Chicago Crime Lab, and author of “Unforgiving Places: The Unexpected Origins of American Gun Violence.”