Get the Lead Out

For a long time, I have had an idea that, when I was silly enough to say it out loud, received more than its share of derision. The idea is a theory I have had concerning the question of why has crime been falling so much in the last decades.

The most famous (and controversial) theory is from Steven Levitt and John Donohue – the Freakonomics Guys – they famously said that the drop in crime is mainly caused by the legalization of abortion in the US – so on and so forth. It is an unsettling theory, though a compelling one.

So I read Freakonomics and found the book to be well written and thought provoking, though I found their crime theory to be not completely convincing. I may have missed something, but they did not close the loop in my mind – they showed plenty of correlation, but failed to indicate causation.

Correlation does not prove causation. Never. Read and remember that. Very few people – and nobody that appears on television understands that simple sentence.

So, what is my theory of the drop in crime?

I have been saying for a long time (years before Freakonomics) – as a matter of fact, I predicted it before it really happened – that a large portion of the drop in crime can be attributed to the removal of lead from gasoline.

You see, for years I have had access to sampling results (some done by me) of lead in both emergency release situations (spills, waste sites, industrial pollution) and in background, “ordinary” locations and situations. Over those years I was repeatedly shocked at the elevated levels of lead near highways, especially in urban areas, and at the blood levels of lead in animals and humans living in those areas. These levels were regularly high enough to expect noticeable behavioral effects. While leaded gas was still being sold, I would talk about how I thought that was one environmental hazard that was more serious than anyone thought (and there were plenty of others that I thought/think weren’t/aren’t so important). When the tetraethyl lead anti-knock compounds were formulated out, I felt that we would see an improvement in behaviors from the populations (mostly densely urban) that were exposed to lead residues fairly quickly as the lead dissipated.

Nobody took my rantings seriously. I had one female actually tell me, “That is so typical, for a man to blame something like the drop in crime on some chemical.”

That didn’t make me very happy. My response was, “Well, I think it’s a typical response for a man that has had years of access to large numbers of lead sampling results and who has studied the dangers and effects of lead exposure to the point of doing work on protecting elements of the population from the possible effects of heavy metal poisoning.” She gave me a very dirty look and refused to talk to me any more. It’s no surprise I could never get dates.

I’m not sure what she objected to… was it my refusal to acknowledge the importance of unicorn saliva in making the world a friendlier place? This was before the Freakanomics book, so it couldn’t be a pro-choice argument (though that is a slippery slope point of view that nobody, rightly so, would touch with a ten foot pole). Now, I am very aware of the, “If all you have is a hammer, everything begins to look like a nail,” principle, and concede that there is a lot of that at work, but that still doesn’t mean I was wrong.

You see, unlike most people, and all pundits and politicians, I looked at the data first – then made predictions from the data – then tested this against reality. There is a huge difference between operating from data first and doing what the pundits and polititians do – coming up with some cute theory that you can benefit from and then searching for data to support it.

Well, now that I’ve dug up all this dirty laundry, what is the point? Someone else has come up with the same idea. After all these years, the New York Times has come out with an article that agrees with my point about lead levels and crime rates. There is a detailed study (pdf) that talks about it.

Of course, there are already articles that contradict the theory and I’m sure we will see more.

So what do I think? More importantly, what do I think now?

As I get older and more experienced (and more muddled and more cranky) I have come to believe the disconnect between correlation and causation is even more tenuous that we think. I’m beginning to believe that it is only under very rare and special conditions that we can even talk about causation in a confident way. I think that chaos (mathematical chaos, not philosophical chaos) rules almost everything we do – feedback loops, sensitivity to initial conditions, and unintended results are the norm, not the exception. I think that we are fooling ourselves when we think we know what’s going on and why.

So after decades of thought and research – why do I think that the crime rate is decreasing? Is Batman a transvestite? Who knows? I think the important thing is to remember to enjoy the walk in the evening that we were too scared to take a decade ago.

Here is an old, bad photo of me working on the Geneva Superfund Site in South Houston, Texas. Circa 1983. It's no wonder I couldn't get dates.

What I learned this week, September 2, 2011

Amy Tan on Creativity


I have been around the block a few times – I have lived long enough to have ridden the economic roller coaster in its up and downs. I’ve been telling folks that the last few years have felt a lot like the Jimmy Carter “malaise” stagflation of 1981.

There are a lot of parallels, and everything fades in memory, especially the worst things, but man, this one is nasty. I keep meeting people, hearing things, and reading more and more about this sort of situation:

“I don’t think anybody realized you had to recreate yourself out of the box,” Wiedemer says, noting that she has a BS in Finance and a dozen years of experience in the financial services industry. “If I had it to do over I wouldn’t climb the ladder in corporate America… Whenever I was unemployed in the past it was never for more than a couple weeks.”

Damn This Recession! – The rise of the unemployees


I added a long TED talk to my blog post on Douglas Adams. If you are a fan of him or of The Hitchiker’s Guide to the Galaxy, go take a look. Don’t forget your towel.


There have been a lot of theories about the cause(s) of the drastic drop in the crime rate over the last few decades. There is certainly more than one explanation. The popular book, Freakonomics, attributes a lot of the drop in crime to the rising abortion rate. Obviously, our increased prison population and more police on the street had a part.

One idea that I always had is the fact that lead was removed from gasoline at the time. This resulted in a dramatic reduction in lead levels, especially in young people, especially in urban areas. Elevated lead levels are associated with aggressive behavior and other mental problems.

I have been criticised for this view; someone told me, “Only a man would think of something like that,” which I thought was pretty idiotic. My personal response was, “Only a person with access to environmental lead data, who had done blood level testing in elevated lead exposure situations (after the Livingston Train Derailment in 1982), and who had done research into how elevated blood lead levels lead to changes in behavior, would think of something like that.”

Finally, I actually found an article that also mentions this theory:

There may also be a medical reason for the crime decline. For decades, doctors have known that children with lots of lead in their blood are much more likely to be aggressive, violent, and delinquent. In 1974, the Environmental Protection Agency required oil companies to stop putting lead in gasoline. At the same time, lead in paint was banned for any new home (though old buildings still have lead paint, which children can absorb). Tests have shown that the amount of lead in Americans’ blood fell by four-fifths between 1975 and 1991. A 2000 study by economist Rick Nevin suggested that the reduction in gasoline lead produced more than half of the decline in violent crime during the nineties. A later study by Nevin claimed that this also happened in other nations. Another economist, Jessica Wolpaw Reyes, has made the same argument. (One oddity about this fascinating claim has yet to be explained: why the reduction related to lead-free blood included only violent crime, not property offenses.)

From Crime and the Great Recession by James Q. Wilson, in City Journal


No matter how bad I am, I’ll never be as bad as this:


Writing Tips for the Week

How to Stay Motivated

Condensed from Colombia University Graduate School of Arts and Sciences

1. Set a daily writing goal.

2. Schedule your writing as early as possible in the day. If you fear or dislike writing, then once it’s done, you experience a tremendous sense of relief that you have the rest of the day to do everything else you must do…without having to think about your writing.

3. Think ahead and plan backwards.

4. Work with deadlines.

5. There is no writing, only re-writing, Lamott (1994) says, “Get it down, so you can clean it up.” Shaw (1993) says, “There is no such thing as good writing. There is only good rewriting.” If it helps to motivate you, you do not need to write a final draft, or even a good draft. You write today what you must so that you can produce good writing when you edit.

6. Reward progress.

7. Motivate (and comfort) yourself with stories of other good writers (and how they suffer, too).

8. Read others’ acknowledgments.

9. And here’s another good motivational strategy: Donate $5 to your favorite U.S. presidential candidate’s opponent for each day you do not write.


Do you ever watch the Discovery Channel’s Dirty Jobs?

I have had the experience of actually doing a job, at the exact location, that was on the show (it wasn’t a bad job at all – and it certainly wasn’t “dirty”).

Salt Mine – Outside

Yes, I used to work there.

At a quick glance – “Dirty Jobs” is just another cheapy, throwaway, cable pseudo-reality series that gives you a few chuckles and a shock or two – barely enough to keep your hand off of the remote control and certainly not enough to justify wasting that precious sliver of time that it takes to watch the thing.

But maybe there’s something else going on here. Maybe you can learn something.

Take a look at this TED talk (yes, all of it) – the host certainly has learned something

Did you think you would get a lecture from the Dirty Jobs guy on Anagnorisis and Peripeteia? With the added instructional lecture on how to bite off a pair of sheep balls?

Stay tuned my friends, you might learn something.