Crime and Incarceration, Cause and Correlation

I was wondering more about this topic. I came across these articles a while back and came across them again.

I’m not entirely sure what conclusion we can make, but obviously there is no simple causal relationship between increasing incarceration and decreasing crime. If anything, the strongest evidence points to decreasing lead as the main factor. Still, it is probably multiple factors accumulating and exacerbating one another, from institutional racism to the problems of poverty in a highly unequal society.

It is obviously long past time to rethink our public policies on crime and incarceration.

Hiring more police officers and throwing more people into prison does not reduce crime — in fact, those states which pursue this strategy tend to have the highest crime rates. And this is true internationally as well; the nations with the toughest approach to crime have the most of it. What are the real causes crime? Scholars lately have been drawn to two particular explanations: media violence and income inequality.

[…] Some may object that international comparisons are like apples and oranges. However, that objection misses the point: if the many social differences of these nations contribute to a lower crime rate, Americans should consider adopting these social policies for themselves. Almost universally, these other nations have abolished the death penalty, practice gun control, and feature less police brutality and more liberal courts. On a less crime-related basis, these other nations also have greater social benefits, less inequality of wealth, larger public sectors and more democratic participation.

In a series of studies published in 2009, the University of Missouri-St. Louis criminologist Richard Rosenfeld and the SUNY-Albany sociologist Steven Messner found that during the last 15 years, states with lower incarceration rates saw bigger drops in crime, on average, than those with lock-’em-up policies. Moreover, the historic increase in the prison population began in the early 1980s, a decade after the crime rate began to rise and a decade before it started to fall. The incarceration rate increased by more than 100 percent in the 1980s, but violent crime still increased that decade, by 22 percent.

If it wasn’t incarceration, what caused the drop? There is no shortage of theories: Scholars have pointed to everything from the legalization of abortion to the prohibition of lead-based paints. Other theories credit America’s aging population (the vast majority of criminals are under 30), President Bill Clinton’s program to put more cops on the street, and either stronger gun control laws or an increase in gun carrying by law-abiding Americans.

The studies behind all these theories claim to produce statistically significant results. Could they all be right?

“I don’t think any of them are right,” says Sam Walker, an emeritus professor of criminal justice at the University of Nebraska. Walker has studied crime for 35 years and has written 13 books on criminal justice. “You can alter variables to make them say whatever you want them to say,” he says. “Conservatives say the crime drop was because of incarceration. Liberals say it was programs like community policing. I don’t think there’s much convincing evidence for either.”

[…] Walker worries that the lack of consensus about specific policies behind the crime drop indicates a failure of academic criminology. “If we could find a cause,” he says, “then we would have a prescription.”

But of the two causal explanations that have found the most support, one—the economy—had nothing to do with crime policy. The other, the petering out of the crack epidemic, was simply a return to normal after weathering the effects of a bad policy. Once distributors of the new drug had established turf, levels of violence returned to normal.

It could be that we have less crime now not because of any brilliant anti-crime initiatives dreamed up by academics and politicians but because civil society has quietly churned out benefits independent of those policies. Maybe the real lesson of the last two decades is that anti-crime policies at best have little effect on the crime rate. When you factor in the drug war, they may make it worse.

While the numbers make it clear that crime is going down, there is no consensus as to why. Any number of things could be going on, said Alfred Blumstein, professor of public policy at Carnegie Mellon University in Pittsburg. Some theories include higher rates of incarceration, reductions in exposure to lead, legalization of abortion and the stabilization of the crack cocaine market. Blumstein argues that these explanations apply only to reductions in crime between 1993 and 2000.


While some, including experts like Porter, suggest that high incarceration rates represent both a miscarriage of justice and a significant financial burden on taxpayers, others argue these policies have made America a safer place. For example, a study from The Heritage Foundation, a conservative think tank based in Washington D.C, concluded that putting so many people behind bars has removed a criminal cohort from the streets and reduced crime.

Critics of this explanation argue that there isn’t a perfect relationship between crime and punishment. “Incarceration was growing in the late 1980’s which is when crime was also increasing,” Blumstein said.


Criminologists expected the crime rate to go up significantly in 2009 because of the great recession, and as Blumstein points out, “we tend to expect crime to rise in a bad economy.” But that isn’t what happened. Crime actually went down nearly ten percent that year. By 2010 things had stabilized with crime falling again between one to two percentage points a year.

None of the explanations for the reductions between 1993 and 2000 make sense for 2009, according to Blumstein. “Those phenomena were all gradual so we’d expect to see gradual reductions like we did between 1993 and 2000,” he said. Crime just plummeted in 2009. Whatever caused it is likely a discrete event, not a policy change, he said.

Blumstein’s theory is that the election Barack Obama, the first black president, broadened young people’s vision of what is possible for their lives. This was especially true among young black men, whose crime rates during that year fell at almost twice the rate of their peers. Blumstein admits that more work needs to be done to evaluate this hypothesis. “It may just be a marginal effect and we need to do more research to see if [the Obama effect] shows up in other places,” he said, “But it is certainly plausible.”

Several other prominent sociologists share with Blumstein the view that the 2009 dip in crime was a result of the election of President Obama. For example, Ohio State University’s Randolph Roth argues that Obama’s election reengaged black Americans in the political process. “The inauguration of the first black president…re-legitimized the government in the eyes of many African-Americans.” he wrote, “It is likely that their greater trust in the political process and their positive feelings about the new president led to lower rates of urban violence.”

Yale sociologist Elijah Anderson believes Obama’s election had a more psychological impact on Black Americans. “Now we have a sense of future,” he said in a 2011 interview with Slate. “All of a sudden you have a stake. That stake is extremely important. If you have a stake, now there’s risk — you realize the consequences of compromising an unknowable future.”

But now, it seems that some new data from Washington, DC is challenging that long-held assertion that the out of control vaginas of the 47% are leading to big, slutty crime rates — over the last 20 years, the murder rate in the District has dropped 75%, while the percentage of single mothers has remained steady. Sorry you got blamed for all that murder, poor ladies.

Back in the early 1990’s, Washington was a pretty bloody place, with about 450 homicides per year. Fast forward twentyish years, and it looks like the capitol will finish up 2012 with fewer than 100 homicides. The population is about the same now as it was then and, to throw a wrench into the conservative theory that marriage is a panacea, the percentage of children with single mothers is also just about identical. Crime is dropping without the all-important socially forced nuclear family structure! What in the name of Murphy Brown is happening?!

In a piece for The Atlantic, University of Maryland professor Philip Cohen notes that media outlets have attributed the recent drop in DC’s murder rate to a rise in average income and improved law enforcement, but that back in the day when things were bad, they didn’t blame a lack of law enforcement or heightened poverty — they blamed single mothers. Cohen quotes a 1985 op-ed from the Washington Post that wrings its hands over “the growing instability of urban black family structure and the creation of an underclass of young men capable of killing for a warmup jacket or a pair of running shoes.” Another cringeworthy bit, this one from a member of the first George Bush administration, warned that “the collapse of the American family in the past few decades is historically unprecedented in the U.S., and possibly in the world. Nowhere is this trend more apparent than in the black community.” In other words, when things are bad, blame single, black women. When things are good, thank the hard work of everyone but single, black women.

Cohen points out that while children of single parents are statistically more likely to commit crimes (Say it with me, folks:),correlation is not causation. That is, the fact that children of single parents (usually mothers) are more likely to commit crimes isn’t simply because their mother has a naked ring finger and a giant, invisible scarlet A pinned on her child’s birth certificate; other, more important factors are in play. Poverty, crappy education, wide availability of guns, the drug trade all contribute to crime in a much larger way than simply not having a dad does.

Despite the convenience of the Single Moms Cause Crimes And Must Be Stopped myth to the conservative cause, Cohen thinks its days are numbered, because the numbers simply don’t bear it out:

Violent crime has fallen through the floor (or at least back to the rates of the 1970s) relative to the bad old days. And this is true not just for homicide but also for rape and other assaults. At the same time, the decline of marriage has continued apace. Looking at two aggregate trends is never enough to tell a whole story of social change, of course. However, if two trends going together doesn’t prove a causal relationship, the opposite is not quite as true. If two trends do not go together, the theory that one causes the other has a steeper hill to climb. In the case of family breakdown driving crime rates, I don’t think the story will make it anymore.

Wolpaw-Reyes gathered lead data from each state, including figures for gasoline sales. She plotted the crime rates in each area and then used common statistical techniques to exclude other factors that could cause crime. Her results backed the lead-crime hypothesis.

“There is a substantial causal relationship,” she says. “I can see it in the state-to-state variations. States that experienced particularly early or particularly sharp declines in lead experienced particularly early or particularly sharp declines in violent crime 20 years later.”

She says her research also established different levels of crime in states with high and low lead rates.

Nevin’s original research pointed to lead poisoning in childhood increasing the likelihood of offending by the time someone had reached their teens or early twenties. Wolpaw-Reyes’ data appeared to show that anti-pollution legislation in the US then reversed that trend on a state-by-state basis.

“Lead changes who we are,” she says. “If you wanted to say, Jessica, I don’t believe that story, then my answer is that you need to come up with another story that would explain why we have found this particular pattern to lead in the 1970s and 80s and then crime in the 1990s and 2000s.

“Moreover you need to be able to show why this relationship is now coming up in other work on bullying, child behaviour problems, teenage delinquency, suicide and substance abuse. You need to tell a story about why those would be linked by chance.”

Since then, the data for the lead theorists has become more and more detailed. Nevin and his supporters predicted that crime would fall in other nations 20 years after the banning of leaded petrol–and their theory appears to have played out in Europe.

Leaded petrol was removed from British engines later than in North America–and the crime rate in the UK began to fall later than in the US and Canada.

Lead theorists say that data they’ve collated and calculated from each nation shows the same 20-year trend–the sooner lead is removed from the environment, the sooner crime will begin to fall.

Dr Bernard Gesch says the data now suggests that lead could account for as much as 90% of the changing crime rate during the 20th Century across all of the world.

Twitter brought me this link this morning and it’s full of facts that might surprise you.

In the last 20 years in particular, the FBI reports, rates of crime amongAfrican American youth have plummeted: All offenses (down 47%), drug offenses (down 50%), property offenses (down 51%), serious Part I offenses (down 53%), assault (down 59%), robbery (down 60%), all violent offenses (down 60%), rape (down 66%), and murder (down 82%).New, 2012 figures from California’s Criminal Justice Statistics Center reveal that the state’s black youth show the lowest level of homicide arrest since statewide racial tabulations were first assembled in 1960. Nearly every type of offense—felony, misdemeanor, and status—is much rarer among black youth today than in past generations.

There’s more. The drop in crime hasn’t followed get-tough policies. The number of black youths jailed in California, for example, has dropped sharply. The numbers in the article by Mike Males at the Center on Juvenile and Criminal Justice are staggering. I’d be interested in some similar comparisons in Arkansas between 1990 and today.

Males contends that this is big news that runs counter to the narratives from every media and public official. Why doesn’t it get attention?

The sad reality is that authorities, academic experts, politicians, and geriatric-media reporters (the average age of news consumers is well over 50) of 2013 simply do not know how to deal with a young black population that is not committing shootings, robberies, drug mayhem, andgangsterisms in mass numbers—let alone one that is dramatically less criminal than the older generations deploring them….

America’s warped crime and social policy establishment badly needs black youth to be killers and thugs, to retreat into the comforts of 1990, nostalgia for a past that never existed, and smug, politically and fiscally profitable prophecies of demographic doom. In America of 2013, just as in 1913, feared scapegoats on which to blame social problems remain a hotter commodity than scientific analysis and effective policy.

I should note that a quick check shows government-compiled arrest rates among black juveniles remain higher, but they are nonetheless dropping. (Some have theorized — if you’re looking for another surprising idea — that a contributing cause could be the higher exposure among poor kids to lead-based paint.) Still eye-opening.

“Correlation is not causation!” And that’s true. If this curve were the only bit of evidence we had, the connection between lead and violent crime would be pretty thin. But it’s not. You should read the story to understand just how many different studies confirm this relationship. In addition, over the last decade there’s been a tsunami of new medical research about just what lead poisoning—even at very low levels—does to children. It lowers IQ, of course,but it does a lot more than that:

Not only does lead promote apoptosis, or cell death, in the brain, but the element is also chemically similar to calcium. When it settles in cerebral tissue, it prevents calcium ions from doing their job, something that causes physical damage to the developing brain that persists into adulthood.

Only in the last few years have we begun to understand exactly what effects this has. A team of researchers at the University of Cincinnati has been following a group of 300 children for more than 30 years and recently performed a series of MRI scans that highlighted the neurological differences between subjects who had high and low exposure to lead during early childhood.

One set of scans found that lead exposure is linked to production of the brain’s white matter—primarily a substance called myelin, which forms an insulating sheath around the connections between neurons. Lead exposure degrades both the formation and structure of myelin, and when this happens, says Kim Dietrich, one of the leaders of the imaging studies, “neurons are not communicating effectively.” Put simply, the network connections within the brain become both slower and less coordinated.

A second study found that high exposure to lead during childhood was linked to a permanent loss of gray matter in the prefrontal cortex—a part of the brain associated with aggression control as well as what psychologists call “executive functions”: emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility. One way to understand this, says Kim Cecil, another member of the Cincinnati team, is that lead affects precisely the areas of the brain “that make us most human.”

So lead is a double whammy: It impairs specific parts of the brain responsible for executive functions and it impairs the communication channels between these parts of the brain. For children like the ones in the Cincinnati study, who were mostly inner-city kids with plenty of strikes against them already, lead exposure was, in Cecil’s words, an “additional kick in the gut.”

We now have a huge amount of evidence linking lead to violent crime. We have evidence not just at the national level, but also at the state level, the city level, and the international level. We have longitudinal studies that track children from birth to adulthood to find out if higher blood lead levels lead to more arrests for violent crimes. And perhaps most important, this is a theory that just makes sense. Everything we now know about the effects of lead on the brain tells us that even moderately high levels of lead exposure are associated with aggressivity, impulsivity, ADHD, and lower IQ. And right there, you’ve practically defined the profile of a violent young offender.

3 thoughts on “Crime and Incarceration, Cause and Correlation

    • That is a depressing but unsurprising percentage. If we included the entire data from the past century, it would be much higher still. I suspect that historically speaking for blacks in the US innocent death sentences have been the rule instead of the exception. Blacks are still disproportionately found on death row, despite there being more whites and hence more white criminals in the country.

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