Is Jamaica's dramatic drop in crime due to policing or unleaded gas?

"Police chiefs 'want to think what they do on a daily basis matters,' says a public health expert. 'And it does.' But maybe not as much as they think." (cited by Kevin Drum in Mother Jones)

In a recent NY Times1 article, the author Damien Cave celebrates the dramatic drop in violent crime in Jamaica and sees Jamaica as emerging, "as a rare bright spot in the hub of the fight against drugs and organized crime that extends across South America and the Caribbean."

He argues that a new emphasis on community policing, violence reduction and combating corruption has helped reduce Jamaica’s murder rate by 40 percent since 2009.

He notes that:

Since 2009, no other country has received more American aid from the $203 million Caribbean Basin Security Initiative, yet relatively little of it has been directed toward the muscular, militarized efforts financed elsewhere as part of the war on drugs.

Jamaica received more money from the Caribbean Basin Security initiative than any other country but chose to spend it on community policing, violence reduction and combating corruption.

Mr. Cave sees the capture and extradition of drug lord Christopher Dudus Coke as the signature event in the decline of violent crime in Jamaica.

He argues argues that:

The new emphasis — on community policing, violence reduction and combating corruption — grew partly from crisis. In May 2010, Christopher M. Coke, one of Jamaica’s most powerful drug lords, fought an attempt to arrest and extradite him to the United States, prompting a neighborhood siege by the authorities, which left at least 70 people dead. 

His surrender a few weeks later helped break up gun and drug networks, according to Jamaican officials, and allowed the country to zero in on longer-term projects, with imported expertise.

Christopher Dudus Coke

He cites Eduardo A. Gamarra, a professor of international relations at Florida International University, who said:

Jamaica’s approach had taken hold only because the arrest of Mr. Coke forced residents to see their country at rock bottom. A tipping point was reached, he said, as Jamaicans witnessed the power of Mr. Coke (nicknamed Dudus), who avoided extradition for nearly a year with the help of well-connected political allies, and as bodies piled up from the conflict between his supporters and the authorities.

You have to have these momentous events to transform societies, Mr. Gamarra said. What is it that produced the change in Jamaica? Dudus Coke.

The following day, Matthew Yglesias writing in Slate2 magazine took quite a different view. He credited the decline in violent crime in Jamaica in part to Jamaica's phasing out of leaded gasoline. 

He notes that:

From 1990 to 2000, Jamaica started phasing out leaded gasoline. From 2009 to 2013, the crime rate has fallen forty percent. In other words, Jamaica is likely starting to see the beneficial impact of a youth cohort with lower levels of lead poisoning. And just based on the lead channel alone you'd expect to see meaningful further improvements over the next 5-10 years as the kids who were born after the complete eradication of leaded gasoline grow up.

Yglesias bases his arguments on  findings from a growing body of research, mainly in the United States, linking lead exposure in small children with a whole range of complications later in life, including lower IQ, hyperactivity, behavioral problems, and learning disabilities. The research is aptly summarized by Kevin Drum in his article in Mother Jones3 magazine, published in February, this year.

In that article Kevin Drum argues that Pb(CH2CH3)4 tetraethyl lead, the gasoline additive in leaded gasoline that was invented by General Motors in the 1920s to prevent knocking and pinging in engines is, "the hidden villain behind violent crime, lower IQs, and even the ADHD epidemic."

The findings stem from work done by Rick Nevin who worked as a consultant for the US Department of Housing and Urban Development in 1994 on the costs and benefits of removing lead paint from old houses.

According to Nevin as cited by Drum:

The biggest source of lead in the postwar era, it turns out, wasn't paint. It was leaded gasoline. Lead emissions from (automobile) tailpipes rose steadily from the early '40s through the early '70s, nearly quadrupling over that period. Then, as unleaded gasoline began to replace leaded gasoline, emissions plummeted.

Gasoline lead may explain as much as 90 percent of the rise and fall of violent crime over the past half century.

In a 2000 paper Nevin had concluded:

"..that if you add a lag time of 23 years (the time it takes an infant to grow up), lead emissions from automobiles explain 90 percent of the variation in violent crime in America. Toddlers who ingested high levels of lead in the '40s and '50s really were more likely to become violent criminals in the '60s, '70s, and '80s."

Drum notes that crime rose everywhere in the US at once in the '60s and '70s and fell in the '90s. 

During the '70s and '80s, the introduction of the catalytic converter, combined with increasingly stringent Environmental Protection Agency rules, steadily reduced the amount of leaded gasoline used in America, ... this reduction wasn't uniform. In states where consumption of leaded gasoline declined slowly, crime declined slowly. Where it declined quickly, crime declined quickly. lead levels in gasoline decreased, the differences (in crime rates) between big and small cities largely went away. And guess what? The difference in murder rates went away too. Today, homicide rates are similar in cities of all sizes. It may be that violent crime isn't an inevitable consequence of being a big city after all.

Many theories have been advanced for the explosion and subsequent across the board decline of crime in the US.

However, one of the theories most credited with crime reduction in the US is the so-called "broken windows" model of fighting crime which is somewhat analogous to the community based model followed by Jamaica.

It is celebrated because it is the approach taken by former New York City mayor Rudolph Giuliani and his police chief William Bratton in their much celebrated reduction of crime in New York City. It is well documented and critiqued by Drum in his article and a summary may be useful for assessing the relevance of policing in the Jamaican situation. 

When Giuliani became mayor, he embraced the theory of crime fighting called "broken windows," popularized by James Q. Wilson and George L. Kelling in an article in The Atlantic a decade earlier. "If a window in a building is broken and is left unrepaired," the theory goes, "all the rest of the windows will soon be broken." Likewise, tolerance of small crimes create a vicious cycle leading to larger crimes and resulting in entire neighborhoods turning into war zones. However, if you crack down on small crimes, bigger crimes fall as well.

As cited by Drum, the results of Giuliani's approach seemed dramatic.

In 1996, the New York Times reported that crime had plunged for the third straight year, the sharpest drop since the end of Prohibition. Since 1993, rape rates had dropped 17 percent, assault 27 percent, robbery 42 percent, and murder an astonishing 49 percent. Giuliani was on his way to becoming America's Mayor and Bratton was on the cover of Time. It was a remarkable public policy victory.

Drum notes that some criminologists had predicted that the demographic bulge, the large number of baby boomers having a correspondingly large number of children growing to adulthood, would lead to additional crime. But although the bulge came right on schedule, "..crime continued to drop. And drop. And drop. By 2010, violent crime rates in New York City had plunged 75 percent from their peak in the early '90s."

He notes:

For one thing, violent crime actually peaked in New York City in 1990, four years before the Giuliani-Bratton era. By the time they took office, it had already dropped 12 percent.

...far more puzzling, it's not just New York that has seen a big drop in crime. In city after city, violent crime peaked in the early '90s and then began a steady and spectacular decline. Washington, DC, didn't have either Giuliani or Bratton, but its violent crime rate has dropped 58 percent since its peak. Dallas' has fallen 70 percent. Newark: 74 percent. Los Angeles: 78 percent.

Perhaps the biggest challenge to conventional wisdom was that even in the "Great Recession" crime in the US continued to fall. Drum notes:

Crime goes down when the economy is booming and goes up when it's in a slump. Unfortunately, the theory doesn't seem to hold water—for example, crime rates have continued to drop recently despite our prolonged downturn.

Back to Nevin whose research spearheaded the theory that lead poisoning is the culprit in the rise and subsequent decline of crime.

Nevin has collected data correlating the rise and fall in leaded gasoline usage with the rise and fall in crime in Australia, Canada, Great Britain, Finland, France, Italy, New Zealand, and Germany. In every case the use of leaded gasoline and the subsequent increase in crime and disuse of leaded gasoline and the subsequent decline in crime, " each other astonishingly well." According to Drum, Nevin has not found a single country that does not fit his theory. 

Drum notes that there is now an astonishing body of evidence based on international, national, state, city, and even the individual level that supports the theory that the upsurge in violent crime and its subsequent dramatic decline is due to use and subsequent disuse of lead as an additive in gasoline.

If the theory holds true, Jamaica and the entire violent Caribbean has much to be hopeful for, at least to the extend leaded gasoline is no longer used. Residual lead that still contaminates the soil and living spaces will continue to adversely affect IQ and crime but for all intents we may be witnessing the leading edge of the end of the crime wave that has convulsed Jamaica and the rest of the Caribbean.

1: NY Times, August 17, 2013

2: Slate, August 18, 2013

3: Mother Jones, January/February 2013