One of the most astonishing facts that I learned recently is the steady and incredible fall in all types of crime in the last two decades years. Overall crime and violent crime have fallen 55% and 51%, respectively since they peaked in 1991. Yes, you read that right. Across the board, crime has fallen over 50% in the last two decades. You would think that such an incredible improvement in one of the most important aspects of life (safety) would be an indelible part of the American experience in the last 20 years. However, Americans think crime is getting worse every year and feel as unsafe as they did in the 90s, when crime was over 90% higher!
The question as to why there is such a significant gap between perception and reality when it comes to crime is an interesting and important question. Why is the American public unaware of this incredibly good news?!?
Crime increased drastically in the 70s and 80s in the US and peaked in the early 90s. Since then, it has been falling precipitously and now is back to the the levels of the halycon days of the 60s. Understanding the causes of the incredible rise and fall of crime has incredible consequences for society. There are numerous explanations for the crime pattern: more and improved policing, economic conditions, the reversal of the crack epidemic, and demographics are a few of the explanations. However, in my reading, the most compelling explanation is one that you have likely never heard of: lead exposure.
The graph above shows the time trends of two variables with a 23 year lag: (1) violent crime per capita; (2) childhood exposure to lead. Incredibly, there is almost perfect correlation - higher/lower exposure to lead as a child is correlated with higher/lower crime committed by those kids 23 years later. The 23 year time lag is important because most crime is committed by adults in their 20s.
But as we all know, correlation is not causation - there may be many other variables with a similar time trend. In an example of quality journalism, Kevin Jones documents and summarizes the economic and scientific literature linking lead exposure and crime. Researches have found the same pattern above, not just for the US, but for many other countries as well. Also, they find that variations in lead reduction at the state-level can largely explain difference in crime reduction across the states. They find the same patterns at the local level. In addition to the strong econometric findings, there is also physiological evidence linking lead exposure to cognitive stunting, poor decision making, attention problems, and higher aggression., characteristics of criminals.
While the book is not closed on this debate, I found the evidence of the link between lead exposure and crime truly compelling. What is remarkable is that the EPA's mandate of the phaseout of leaded gasoline in 1973 and the banning of lead-based paint may have been some of the most socially beneficial policies of our time. And the not full understanding the causes of the dramatic rise and fall of crime led to the mistaken belief that the 3 strikes law in California (which is now finally being rolled back) or the broken windows theory of crime punishment, which were originally believed to have helped reduce crime may have not had a huge impact on crime while locking up millions of people behind bars for petty crimes and destroying their lives unnecessarily.
The question as to why there is such a significant gap between perception and reality when it comes to crime is an interesting and important question. Why is the American public unaware of this incredibly good news?!?
Crime increased drastically in the 70s and 80s in the US and peaked in the early 90s. Since then, it has been falling precipitously and now is back to the the levels of the halycon days of the 60s. Understanding the causes of the incredible rise and fall of crime has incredible consequences for society. There are numerous explanations for the crime pattern: more and improved policing, economic conditions, the reversal of the crack epidemic, and demographics are a few of the explanations. However, in my reading, the most compelling explanation is one that you have likely never heard of: lead exposure.
The graph above shows the time trends of two variables with a 23 year lag: (1) violent crime per capita; (2) childhood exposure to lead. Incredibly, there is almost perfect correlation - higher/lower exposure to lead as a child is correlated with higher/lower crime committed by those kids 23 years later. The 23 year time lag is important because most crime is committed by adults in their 20s.
But as we all know, correlation is not causation - there may be many other variables with a similar time trend. In an example of quality journalism, Kevin Jones documents and summarizes the economic and scientific literature linking lead exposure and crime. Researches have found the same pattern above, not just for the US, but for many other countries as well. Also, they find that variations in lead reduction at the state-level can largely explain difference in crime reduction across the states. They find the same patterns at the local level. In addition to the strong econometric findings, there is also physiological evidence linking lead exposure to cognitive stunting, poor decision making, attention problems, and higher aggression., characteristics of criminals.
While the book is not closed on this debate, I found the evidence of the link between lead exposure and crime truly compelling. What is remarkable is that the EPA's mandate of the phaseout of leaded gasoline in 1973 and the banning of lead-based paint may have been some of the most socially beneficial policies of our time. And the not full understanding the causes of the dramatic rise and fall of crime led to the mistaken belief that the 3 strikes law in California (which is now finally being rolled back) or the broken windows theory of crime punishment, which were originally believed to have helped reduce crime may have not had a huge impact on crime while locking up millions of people behind bars for petty crimes and destroying their lives unnecessarily.
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