I got into a good-natured argument with my friend Pete Wehner of the Ethics and Public Policy Center over lunch last week about the importance of incarceration in explaining the gratifying drop in crime since the 1990s. Pete cited some credible technical analyses (summarized in John DiIulio’s fine overview on crime trends showing that increased incarceration accounts for only 10 to 35 percent of the reduction in crime), while I muttered that we would see how true that is if we freed a whole lot of violent criminals. Without pretending to refute the technical analyses, let me give a quick illustration why I think simple incapacitation—we’ve locked up a huge percentage of the really nasty guys—plus a substantial deterrent effect is a plausible explanation for why violent crime dropped at all.
I specify violent because I’m sure that much of the drop in property crime is explained by target hardening. It’s impossible to steal most new cars this day because there is no way to get the engine started without the key. Hot-wiring is futile. Try to burgle a home in a neighborhood where homes have much worth stealing, and you’d better be prepared to get in and out before the high-tech security system brings the cops. If you’re in a commercial area, you’ve got omnipresent surveillance cameras to worry about along with the security systems. The effect of these innovations on violent crime has been much spottier. Yes, it can be harder to rob a convenience store (robbery is classified as a violent crime), but for the most part, robbery, homicide, aggravated assault, and rape are not technically more difficult to commit than they used to be.
Here is a graph that shows the violent crime rate per 100,000 population and the number of prisoners per 1,000 violent offenses from 1960–2010:
Source: Bureau of Justice Statistics, FBI Uniform Crime Reports. “Prisoners” refers to inmates of state and federal prisons and does not include persons in jail.
The red line shows the shape of two trends: the risk of going to prison if you commit a violent crime and the proportion of all violent criminals who are behind bars at a given time (they are not the actual risks and proportions for various reasons, including the large number of persons in jail who are not included in the count of prisoners—748,728 in 2010). Here’s how I interpret those shapes:
When crime gets safer, crime goes up very quickly as a response. In the late 1950s, the “prison only makes people into smarter criminals” school became dominant in criminal justice circles. By the early 1960s, imprisonment rates were plummeting. For that matter, even the raw number of prisoners fell. One consequence was that every cohort of young people saw acquaintances start to get probation for offenses that would have sent them to prison or reform school in the 1950s. I still remember my shock as a 17-year-old in that era when a friend of mine who shoplifted several thousand dollars of clothes from the store where he worked got probation. Once he had been arrested, it had not occurred to me that he wouldn’t go to reform school.
Pushing that toothpaste back into the tube takes a lot longer. Kids who are amazed when a friend gets away with a serious crime aren’t amazed when, say, 19 percent of their friends arrested for a serious crime are incarcerated instead of 15 percent. Understandably, crime continued to rise after imprisonment rates started to rise after 1974. Even in 1990, after 15 years of rising imprisonment rates, the risk of going to prison if you committed a violent crime was still far lower than it had been in 1960.
Cumulatively, however, two things happen. First, more and more of the “dirty 7 percent” of offenders who commit about 50 percent of all crime end up in prison. They cannot commit crimes, except against other criminals. Second, the cumulative impact of much higher imprisonment rates does make an impression—the idea that crime doesn’t pay is no longer completely a joke. For violent crime, the tipping point occurred in 1992, when imprisonment rates were heading straight up. By the time that the imprisonment rate for violent crime reached its 1960 level in 1998, the downward trendline was well established.
So how much of the reduction in violent crime was produced by increased incarceration? This kind of analysis doesn’t tell us. But neither am I sure that the armory of social science quantitative techniques adequately models what has gone on. Here is my simple-minded thought: Suppose we had maintained imprisonment for violent crime at the rate that applied in 1974. In that case, we would have had 276,769 state and federal prisoners in 2010 instead of the 1,518,104 we actually had. Suppose tomorrow we freed 1.2 million inmates from state and federal prisons. Do we really think violent crime would continue to drop at a somewhat slower pace?
In one sense, it is a silly question, as all counter-factuals must be. And I’m not saying that our current incarceration rates are appropriate. We may very well have been in a state of diminishing returns to incarceration for the last decade, as the experts DiIulio cites have argued. But I continue to harbor the belief that without the massive increases in incarceration after the mid 1970s, crime rates wouldn’t have turned around at all. Higher imprisonment was the necessary condition for 100 percent of the reduction in violent crime.