
A Basic Cohort Test of the Lead-Crime Hypothesis - curtis
https://www.motherjones.com/kevin-drum/2018/02/a-basic-cohort-test-of-the-lead-crime-hypothesis/
======
jcranmer
This appears to be a case of "I have my preconceived interpretation of the
data, and I'm not going to see how well other hypotheses match the data."

The main thrust is that the cohort test supports the Lead-Crime Hypothesis
because, on average, 70s kids were more violent than 80s kids were more
violent than 90s. But later in the post, he mentions that there's an important
confounding factor: the crack epidemic, which starts in 1987 and winds down in
the mid-1990s. This would suggest that the increase in crimes over age for
1970s from 17 to 21 or so is fueled in large part (if we look at the later
graph) by the crack epidemic. If you guesstimate that the trend should be
flat-to-declining, then the trend line for the 1970s absent the crack epidemic
is actually rather closer to the 1980s. Similarly the numbers for 1997 and
1998 (for 1980s) seem anomalously high, and should be lowered a bit.

Put it all together, and you'd estimate that removing the suggested effect of
the crack epidemic would be that there is no substantial difference between
the criminality of people born in 1970, 1980, and 1990.

~~~
cimmanom
This hypothesis is often put forth to in the US. The strongest studies of the
lead hypothesis, however, compare data across multiple countries, which
regulated lead-containing paint and gasoline at different times. These studies
demonstrate that crime drops in each country at a similar period after the
decrease in lead exposure, and at a rate that corresponds to the rate of
decrease in lead exposure.

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curtis
If you're looking for more reading on the Lead-Crime Hypothesis, Drum's "An
Updated Lead-Crime Roundup for 2018" ([https://www.motherjones.com/kevin-
drum/2018/02/an-updated-le...](https://www.motherjones.com/kevin-
drum/2018/02/an-updated-lead-crime-roundup-for-2018/)) has a lot more
information. Section 3 has some direct links to research papers, if that's
your thing.

------
InclinedPlane
Undoubtedly lead exposure has had a profound effect on society, and on crime
levels. Lead exposure leads to reduced IQ and increased aggression. But the
crime landscape during the relevant period (the late 20th century) has too
many confounding factors to extract data from it. For one, there's the "crack
epidemic" crime wave of the late '80s and early '90s. During this period the
rate of homicides committed by teens tripled and then went back to previous
levels. Additionally, violent crime is correlated strongly with population
density. And during the late 20th century in the US cities first began to
empty out (due to "white flight") and then began to be repopulated as
"yuppies" working office jobs and living in cities became more a more
desirable "american dream" than the suburban family home and then later as
urban centers became the core of the new tech economy. At the same time,
police enforcement changed dramatically through the '80s, '90s, and later. The
"war on (some) drugs (used by some people)", mass incarceration, etc. These
are all tremendous confounding factors while the underlying "signal" from lead
exposure is expected to be a gradual change over a fairly long period.

~~~
curtis
Separating out the confounding factors is definitely a big problem, but lots
of effort has gone into just that. Drum has been following the Lead-Crime
Hypothesis science since at least 2012. This blog post:
[https://www.motherjones.com/kevin-drum/2018/02/an-updated-
le...](https://www.motherjones.com/kevin-drum/2018/02/an-updated-lead-crime-
roundup-for-2018/) provides an overview, but maybe not an ideal overview just
because it's so long. Section 3 has links to some actual papers, and some of
the other links may ultimately lead to papers, but there's so much of it that
I didn't explore it deeply.

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jupiter90000
“Lead exposure in childhood may have played a small role in rising and falling
crime rates in the USA but it is unlikely to account for the very high
percentage of the decline suggested by the ecological studies” [1]

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829390/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829390/)

~~~
alexandercrohde
I'm not sure why you're posting that link here. In academia, no single study
is treated as conclusive. For example, when scientists observed a 50% decrease
in men's sperm count in the last 30 years, they cited a meta-study which
reviewed data from 185 other studies. [1]

If you look on google scholar. It's trivial to find well over 100 lead-crime
studies. The one you linked to seems to be only published-online, and not a
meta-study, so it's not clear on what basis you (cherry?) picked it.

[https://doi.org/10.1093/humupd/dmx022](https://doi.org/10.1093/humupd/dmx022)

~~~
jupiter90000
For me it's good to have a healthy dose of skepticism about these things,
especially when it comes to social studies. I didn't like the conclusive tone
of the mother jones article personally. The mother jones author does a fairly
amateur analysis and concludes: "I’d say that basic cohort analysis supports
the lead-crime hypothesis, while age analysis might not."

The article I posted is a counterpoint to this in which an academic cohort
study is reviewed finding lead explains less than 1% of the variation in crime
in a cohort, and another cohort study there reviewed found no association
between lead exposure and murder -- so a relevant article to post here, I'd
say.

Do you consider the results in the MJ article to be as robust as a meta-
analysis and if not, do you have the same criticism of that article? (in which
case, fair enough)

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chris_va
"Anyway, this is just a quick, amateur look at the data."

... Yes, yes it is. Statistics can tell you pretty much any answer you want to
hear, if you are not careful.

------
vpribish
Do people generally find mother jones a quality information source? it has
always seemed to me to be a over the line into left-wing-nut territory -
willfully misleading to appeal to their market.

I'd put it as basically a mirror of fox news on this chart :

[https://www.codlrc.org/content/news-sources-journalistic-
qua...](https://www.codlrc.org/content/news-sources-journalistic-quality-
partisan-bias)

~~~
dtornabene
[http://pressthink.org/2010/11/the-view-from-nowhere-
question...](http://pressthink.org/2010/11/the-view-from-nowhere-questions-
and-answers/)

There are other, better, rebuttals but this is from someone who can't really
be impeached on ideological grounds. Also, the idea that Mother Jones is
"left-wing-nut territory" is ....bad. Unless your yardstick is "distance from
more or less explicit white nationalism of breitbart" then Mother Jones is
solidly center-left.

Finally the graph you posted is pretty bad. The Economist is an ideological
chop shop with no bylines that started life as a forum for propoganda
agitating against the Corn Laws. The idea that their minimally distant from an
axis of "minimal bias" is not exactly born out by the facts.

~~~
tgb
My father is a liberal newspaper reporter and describes The Economist as the
best hope for journalism. If you have to stretch to smear it by pointing out
the lack of bylines and its start over 150 years ago, then I have to wonder
what your biases are. The Economist has its slant for sure but your
characterization of it is extreme.

~~~
dtornabene
Not at all, in fact my characterization of it was pretty restrained.

[https://www.thenation.com/article/economist-has-slavery-
prob...](https://www.thenation.com/article/economist-has-slavery-problem/)
[https://www.politico.com/magazine/story/2014/09/economist-
re...](https://www.politico.com/magazine/story/2014/09/economist-review-
slavery-110687) [https://www.colorlines.com/articles/five-problems-
economists...](https://www.colorlines.com/articles/five-problems-economists-
special-report-latinos)

I could add in its tolerance if not open affection for Fidez the anti-semitic
Hungarian political party, or its virulently anti-union posturing, or its
hatred of the welfare state....

I could go on, specifically just about their ideology and how it permeates
everything thats published there, but its a lost cause on this website.

~~~
vpribish
Those articles are not really convincing - two are regarding one book review,
one criticizes the British reader for mispronouncing Spanish names (among
other nit-picks). Those sources are very obviously biased (which is fine) and
don't nearly constitute objective, or moderate, or broadly-accepted source of
commentary.

If you were a regular reader of the Economist you would know how they actually
look at anti-semitism (scornfully), labor-relations (respectful of labor,
critical of populism and unchecked power), the welfare state (maybe
conservative in the UK, downright progressive for the US - see anything they
cover on healthcare).

Their ideology does permeate all of their work. The reason they are so well
respected is that their ideology is well-reasoned, and their research and
writing is very high quality.

