In 1991, the United States had an incredibly high murder rate. There were 9.8 murders for every 100,000 residents. Just the previous year in New York City, 2,245 people were killed. In 2014, just 328 people were murdered, which is an 85% drop. The rate of violent crime in the entire world has been dropping since 1991. The US murder rate is now lower than any year since 1963.

In 1963, the US murder rate was the same as it is now: 4.6 per 100,000. This is less than half the rate from 1991. That year, there were 8640 murders, with the US having a population of 188.4 million. It is important to note that in 1963, it was possible to order firearms through the mail from places like the Sears catalog. Compared to today, firearms were nearly unregulated.

Puerto Rico is a US territory. Until June of 2015, gun laws in Puerto Rico were very strict. They had all of the gun laws that the Brady campaign asks for: permit to own a firearm, heavy restrictions, etc. The Puerto Rican murder rate is among the highest in the world at  26.5. In June, a Federal judge struck down nearly all of Puerto Rico’s gun laws as being a violation of the Second Amendment. it will be interesting to see what happens to the crime rate there.

It isn’t just murders. The US violent crime rate is now 367.9 per 100,000, which is the lowest it has been since the FBI began keeping track of that statistic in 1994. The entire world has been seeing a drop in crime since about 1990. What is fueling this?

There are numerous theories as to why crime is falling, but many of them fail under scrutiny when you consider that there are many differences between nations. Not all nations have increased their police forces. or have aging demographics. There are a couple that jump out at me: The widespread use of antipsychotic medications, and the banning of lead in gasoline and paint. Levels of lead found in human blood were reduced more than 80 percent from 1976 to 1999.

The effect of lead on children’s brains has been well documented: Exposure to the chemical causes aggressive behavior and cognitive delays. Economist Jessica Reyes estimates that phasing out lead was responsible for 56 percent of the reduction in violent crime (although she could find no relationship between lead and property crime). Experts still disagree about how plausible it is that lead alone could have been responsible for such a massive portion of the crime drop on a worldwide basis.

I think the lead theory has some validity. What say ye?

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SiGraybeard · October 25, 2015 at 3:51 pm

Very interesting. Without having read actual papers and looked at their data, we're left with gut hunches. The case for lead being a major factor seems pretty solid. But what about Mercury? "Mad as a hatter" comes from mercury toxicity, too. Mercury restriction was also part of the late '70s cleanup. The "Freakonomics" abortion hypothesis always smelled funny to me, but without real data, I didn't have any way to look at it. Likewise the glib comments about community policing don't seem right when everywhere I read about cities and localities struggling to pay for the policing they have.

I think the answer is multi-factorial.

I think lead is a part of it and maybe even most of the decline, as Jessica Reyes says. I've never seen any of the major explanations (like the summary of 10 studies you link to) include the deterrent effect of concealed carry.

So maybe lead control, mercury control, and concealed carry could account for the vast majority of the crime decline?

Anonymous · October 27, 2015 at 1:47 pm

Got the lead out of gasoline too.

There is at least one study (international in scope) that looks at the correlation between leaded gas and violence and crime since different countries stopped at different times.

in the end, it's probably not one thing, but a matrix of interrelated things.


BTW, the abortion thing made sense to me, but then 'broken windows policing' did too, on first glance. Now I'm convinced that broken windows was nothing but an excuse to go after low hanging fruit, and a license to harass.

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