Violent crime went down in America again last year [2009 — and through 2011; see update below]. According to preliminary statistics from the FBI, the number of violent crimes dropped by about 5 percent from 2008. Given population growth, that means that the rate of violent crime dropped even more. (So did property crime.)
This is a puzzle because (a) violent crime is more common among the poor; (b) the percentage of Americans who are poor has been trending up since about 2000; and (c) the economy tanked last year. One would have expected a rise, not a fall, in violent crime.
But this head-scratcher is just part of a larger puzzle – understanding long-term trends in America’s criminal violence.
The most reliable measure of violent crime is the homicide rate. Americans kill one another at a much higher rate – double, quadruple, or more – than do residents of comparable western European nations. This gap persists despite a roughly 40 percent drop in our homicide rate in the last 15 years or so. Americans have been notably more violent than western Europeans since about the mid- or late 19th century.
This graph shows the American homicide rate over the last century-plus. (An updated graph through 2010 appears near the end of this post.)
The puzzle compounds. We see a cyclical pattern, a high plateau in the 1920s and early ‘30s; a rapid drop of more than half to a low point in the late 1950s; then, a sharp rise, more than doubling, by 1980 and 1990; and then what will probably be a drop of nearly half by 2009. These are huge swings. (Technical note: The early numbers are based on Eckberg’s corrections.)
We can put this story into yet greater perspective with the graph below. The line in that graph represents my rough estimate of fluctuations in the U.S. rate of homicide over many more generations, drawing on the historical literature (see some references at the end of this post). While the details are informed guesses, the general trend is well-established.
The overall story is that homicide rates declined substantially (as did rates of interpersonal violence of all sorts). The drop in violent crime in the U.S. after about 1850 was not as fast or as consistent as it was in western Europe and that is when the striking violence gap opened up. The graph also shows that progress was hardly uniform, as there were many upswings of violence. Spurts often coincide with wars and the aftermaths of war – notably having many demobilized soldiers, trained and armed fighters, roaming the land. (See this paper for one analysis of the war effect.) Another short-term influence is bloody competition among armed criminals – for example, over alcohol distribution during Prohibition and over crack cocaine during the 1980s.
Scholars have offered several explanations for the centuries’-long decline of violence in the West. Here are three common ones:
* Government: Political authorities gained greater policing power and legitimacy. This allowed them to suppress criminal attacks, intergroup battles, and personal feuds. Also, court systems provided a peaceful way to resolve conflicts. And mandatory schooling swept dangerous boys off the streets.
* Economics: Greater and more broadly-distributed wealth reduced people’s motivation for crime and raised the costs of getting into trouble. (Barroom brawling seems less attractive if it will cost you a steady and well-paying job.)
* Culture: Over the centuries, westerners increasingly came to feel that violence was uncouth and distasteful. Historians refer to the “civilizing process,” a phrase German sociologist Norbert Elias used to describe how the royal courts of Europe suppressed bloody feuds among lords. The repression of violence spread to the bourgeois who, in turn, taught it to the working classes – or forced it on them through, for example, schooling. Over time, hitting, knifing, and shooting came to seem (to most people) as vulgar as smelling from body odor or defecating in the castle hallway.
Back to the Present
How might any of this explain the latest – the post-1990 – downswing in homicide and in criminal violence more generally? The rates are now approaching the level of the least violent era in American history, the late 1950s.
Researchers point to some similar factors, although they disagree about their relative importance. Some stress government authority, namely that longer criminal sentences and the prison-building boom kept many more “bad actors” off the streets longer. Others point to the economic boom of the 1990s, when unemployment, even in poor communities, sunk to low levels. And others argue – although it is difficult to confirm with “hard data” – that a cultural shift occurred, that increasing revulsion toward violence eventually spread into even the most violent communities and corners of the United States.
Recently, scholars have added yet another explanation: Immigration. Cities and neighborhoods that have received the largest influx of immigrants (including Mexican immigrants) have had — despite popular stereotypes to the contrary — the largest drops in criminal violence. (See, e.g., here and here.) Thus, increased immigration may explain part of the crime drop since 1990.
In a wider view, perhaps the more puzzling part of the story is the rapid upswing in violence from around 1960 to 1990 (see first graph above). Two generations of scholars have yet (it appears to me) to satisfactorily explain why that happened. Some of the upswing in crime can be attributed to the baby boom: Put a lot more 15-to-25-year-old males into a society and you will get an upsurge of violence. Some of it has to do with what happened in the black ghettos of the North: The population grew rapidly just when the well-paying blue-collar jobs for men were disappearing. Some of it involved the growing drug trade. And perhaps some of the upswing reflected a short-term cultural shift – maybe the baby boom generation’s rejection of authority – that encouraged violence.
Whatever the reason, the latest news – that violent crime in the U.S., although still high by first-world standards, is trending downward – seems consistent with our longer history. It is the upsurge of violent crime starting in the early 1960s and now ending that remains the larger puzzle.
* * *
Update (Jan. 7, 2011)
Violent crime went down in America again last year . According to preliminary statistics from the FBI covering the first half of 2010, the number of violent crimes dropped by about 6 percent from the same period a year before.
An updated (and more finely “smoothed”) version of the first chart shows the continuing drop in homicides:
Update (May 23, 2011)
The final statistics for 2010 were released and they showed a further drop in homicides of over 4%, of violent crimes overall of over 5%, and of robberies of over 9% — all during a high unemployment, long-lasting recession. The experts are flummoxed. As the New York Times reported,
Nationally, the drop in violent crime not only calls into question the theory that crime rates are closely correlated with economic hardship, but another argument as well, said Frank E. Zimring, a law professor at the University of California, Berkeley.
As the percentage of people behind bars has decreased in the past few years, violent crime rates have fallen as well. For those who believed that higher incarceration rates inevitably led to less crime, “this would also be the last time to expect a crime decline,” he said.
Note on Figure:
The basic sources are listed on the chart. Eckberg (1995) corrected the raw federal data for missing states in the early part of the century. I excluded the victims of 9/11. The 2010 point is a rough estimate from the first half of the year.
More (and More) Updates:
(June 16, 2012) — And number of violent crimes kept dropping from 2010 into 2011, the number of murders down about 2% (source) — with property crimes dropping, too, although cutbacks in police forces may artificially account for some of the drop in recorded property crimes. It remains a puzzle.
(January 3, 2013) — As violent crime rates continued to edge down nationwide (although spiking in some cities) in 2011 and 2012, Mother Jones writer Kevin Drum wrote a story arguing, with references to several studies, that he had the answer: the decline in lead in gasoline. Lead affects young brains and undermines the development of “executive function” and self-control. Leaded gasoline increased rapidly in the 1940s through 1960s. The result, 20 years later, was more violent crime from males and more teen pregnancies for females. Then, lead was removed from gasoline and exposure dropped from the ’70s through the ’80s. The result, Drm argues: the drop we saw in violent crime.
As of now, I am agnostic on this theory. It’s certainly not mainstream among criminologists and we’ll have to see the response. My own contribution was an article showing that the rates of violent crime spread from the urban centers to smaller communities in a urban-to-rural diffusion pattern (in Rural Sociology, Fall 1980). I don’t know if lead exposure followed the same path.
(July 24, 2013) — A recent issue of The Economist reports that the crime drop discovered here occurred in roughly the same form and period across much of the developed western world. The story lays out about a dozen different explanations, placing most emphasis on improved security (policing, locks, surveillance, etc.). I’m skeptical, but the puzzle persists.
(June 4, 2015) — Vox presents “16 Theories for Why Crime Plummeted” (including the lead theory) and concludes… shrug.
<> Adler, J. S. 2001. “`Halting the Slaughter of the Innocents’,” Social Science History.
<> Blumstein, A. and J. Wallman (eds.). 2000. The Crime Drop in America.
<> Eckberg, D. L. 1995. “Estimates of Early 20th-Century U.S. Homicide Rates,” Demography.
<> Fischer, C. S. 1980. “The Spread of Crime from City to Countryside,” Rural Sociology.
<> Gurr, T. R. (ed.). 1989. Violence in America, Vol. 1: The History of Crime.
<> Johnson, E., and E. Monkkonen (eds.). 1996. The Civilization of Crime.
<> Lane, R. 1997. Murder in America: A History.
<> Monkkonen, E. H. 2001. Murder in New York City.
<> Rosenfeld, R.. 2002. “The Crime Decline in Context.” Contexts.
<> Zimring, F. E. 2007. The Great American Crime Decline.