America’s most criminogenic drug

Which intoxicating substance is associated with the most lethal violence? Devotees of the Wire might presume that cocaine or maybe heroin would top the list.

Of course the correct answer, by far, is alcohol. It’s involved in more homicides than pretty much every other substance, combined. Surveys of people incarcerated for violent crimes indicate that about 40% had been drinking at the time they committed these offenses. Among those who had been drinking, average blood-alcohol levels were estimated to exceed three times the legal limit.

Aside from its role among perpetrators of violence, alcohol use is widespread among victims, too, for some of the same reasons. Recent data from the Illinois Violent Death Reporting System (IVDRS) bear out these trends. At my request, researchers at the Stanley Manne Children’s Research Institute analyzed 3,016 homicides occurring in five Illinois counties between 2005 and 2009. I find the below figures quite striking, particularly among young people. More here


Lead and crime: a hole in the theory

Kevin Drum, whose “Criminal Element” essay linking violence rates to lead exposure has been (as it deserves to be) extraordinarily influential, links to a BBC story in which a more-than-usually-dim criminologist explains that he disbelieves in the lead-crime link because all biological explanations of crime are outside “the mainstream” (presumably meaning “the mainstream of criminological research”). Kevin is right to say that the multiple levels of evidence for the lead-crime link (brain-imaging work, case-control studies at the individual level, studies of crime changes in neighborhoods that suffered greater and lesser increases in lead exposure after WWII and decreases in lead exposure after the mid-1970s, and cross-national studies) deserve more than a casual blow-off. It’s not, after all, as if “mainstream” criminology had a bunch of well-worked out causal theories with proven predictive power.

Like Kevin, I’ve been frustated that the evidence about lead hasn’t led to more action, if only some serious experimental work removing lead from randomly selected buildings or neighborhoods and then doing developmental measurements on the childen in the chosen areas compared to children in control areas. And I was puzzled when I heard that the hyper-sensible Phil Cook of Duke was among the skeptics.

Alas, Phil seems to have good reason to raise questions, especially about the ultra-strong claims sometimes heard about the percentage of the crime drop since 1994 attributable to changes in lead exposure. (Note that in a system with multiple positive feedbacks, the change-attribution factors needn’t sum to unity, so the claim that “the change in X accounts for 90% of the change in Y” is dubious on its face.)

Cook writes:

My skepticism about the “lead removal” explanation for the crime drop stems from the same source as my skepticism about the Donohue-Levitt explanation in terms of abortion legalization. They have an exact parallel to the previous explanations for the surge in violence of the late ‘80s by John DiIulio and others. The focus in both cases is the character of the kids – the belief that during the 80s the teens were getting “worse,” and during the 90s they were getting “better.” Even a fairly casual glance at the data demonstrates that whatever the cause of the crime surge, and then the crime drop, it was not associated with particular cohorts. It was an environmental effect – 10 cohorts were swept up in the crime surge simultaneously, and the drop has the same correlated pattern.

There is a natural inclination to assume that the reason the murder rate is increasing is because there are more murderers, and the reason we have fewer is that there are fewer murderers. It’s not that I rule out such explanations – I’m open to the idea of lead removal and abortion legalization – it’s just that I don’t think it explains the actual pattern of the youth violence epidemic, either up or down. More generally, my instinct is to look to the social and economic environment to explain large shifts in population outcomes.

Here’s Cook’s paper with John Laub.

Now, since youth violence surely has impacts on adult violence, finding that all the cohorts decreased their violence at the same time doesn’t quite rule out the idea that the younger cohorts were largely driving the train. And those brain-imaging, case-control, neighborhood, and cross-national results are still out there. But Cook’s objection remains a powerful one: the theory predicts that we should have seen the crime declines specifically in the birth cohorts exposed to less lead, and that’s not what we saw in fact.

I’d still like to see some experimental work to figure out how much additional lead removal would turn out to be cost-justified (with crime-reduction benefits a significant, but but not the dominant, part of the benefit story), but the simple story “Crime declined because lead declined” now has a major hole in it. That’s too bad, because attempts to find the relevant social and economic causes haven’t gotten very far. To my mind, the crime boom that started in the late 1950s or early 1960s and the crime bust that started in the mid- 1990s (and other large-scale, decades-long swings up and down in crime rates elsewhere) remain largely unexplained in retrospect, as they were entirely unpredicted in prospect.

Footnote And that, of course, is the difference between science and policy analysis on the one hand and mere advocacy on the other. Of course scientists and analysts are influenced by their values and prejudices. I don’t pretend that Jessica Reyes’s work didn’t make me happy or that Cook’s response doesn’t make me sad. The lead-crime story fits all my political prejudices, as well as my taste for simple and surprising explanations with clear policy implications. And I’ve been a loud advocate for it. But I don’t want to believe it if it isn’t true.

Non-Violent Offenders Have Been a Declining Part of the State Prison Population for 20 Years

Prison is the subject of many myths in the public policy world. For example, many people believe that the size of the prison population has continued to rise under President Obama, when in fact it has fallen. Other observers maintain that prison populations drop during economic downturns, when in fact the reverse has generally been true. An even more widely embraced myth is that states have been increasingly incarcerating prison populations are increasingly composed of non-violent offenders. But as this chart from the Bureau of Justice Statistics (BJS) shows, the proportion of the state prison population that is serving time for a non-violent crime has been declining since the early 1990s.

The BJS data reveal that most state prison inmates today are incarcerated for a violent offense. Importantly, the data reflect current controlling offense only, and thus understate the proportion of prisoners who engage in violence: Many inmates currently serving time for a non-violent offense have prior convictions for violent crimes.

These data have at least three important implications. Continue Reading…

How not to write about Chicago’s crime problem

If you have to write a story about Chicago’s crime problem, you couldn’t do much worse than Kevin Williamson’s “Gangsterville: How Chicago reclaimed the projects but lost the city,” on the web at the National Review.

To be sure, Williamson makes a few good points. He notes, for example, that the decline of disciplined hierarchical gangs may have brought unintended consequences. He reminds the youngsters of notorious Chicago gangsters Larry Hoover and Jeff Fort. In just about every other way, this piece illustrates much that is wrong in the way millions of Americans view the urban scene.

He notes–but variously seems to forget– that it’s not Dodge City here. Chicago homicide rates—though up roughly 20 percent between 2011 and 2012—remain a notch below levels of ten or fifteen years ago. Homicide rates are way below the levels of the early 1990s and the crack epidemic years. Non-homicide crime rates have also declined. Our homicide decline has been too slow when compared with LA or New York. Still, many cities—Baltimore, Detroit, Cleveland, Camden–would love to have Chicago’s problems or our crime rate.

Williamson’s article is filled with homespun wisdom such as the following:

The usual noises were made about gun control, and especially the flow of guns from nearby Indiana into Chicago, though nobody bothered to ask why Chicago is a war zone and Muncie isn’t.

I don’t know about Muncie, which is four hours away. People have bothered to ask about our almost-immediate neighbor: Gary, Indiana. An April 2012 Chicago magazine piece described swathes of Gary’s housing stock as “burned and cratered as if in a war zone.” Continue Reading…