Source? Crime in general decreased quite a lot after the depression, but the use of leaded gasoline was quite prevalent regardless.
There is also the point that the people who did have cars in the 1920s were the aristocrats, and twenty years after that...
This seems to correlate fairly well with the government's war on (certain) drugs as well.
I highly doubt there's one contributing factor to crime, and I highly doubt it is solely from leaded gasoline.
And the answer from this research is quite a lot, because the timing of the rise and fall in crime match the timing of leaded gasoline (with a 20-year lag) across cities, states, and countries.
To say that 'other factors are responsible' would be to posit that there is some other factor that holds both across and within different cultures and countries that perfect accounts for the pattern in crime rates that we see. That seems much harder to believe than simply 'leaded gasoline causes crime', which we both have robust evidence for now, and for which we have a very plausible mechanism of action.
However, I would like to see the specific data that says the following (because I'm not seeing it when I read the article):
"Regardless of the crack epidemic in the 1980s, regardless of the decline in public housing in the 1980s, regardless of the rise of police surveillance technology, we have indisputable evidence that lead in the blood causes an increase in crime locally and nationwide by XMeaningfulPercent".
I'd be surprised if one could ever make such a statement.
The data we currently have shows that someone born in 1960 and committing a crime in 1985 has been exposed to lead, but they also might have been exposed to crack. Additionally, declining government project housing provided strong protection for criminals to hide from police, and the police surveillance technology in 1985 was pitiful compared to the massive levels of surveillance now.
None of these factors exist anymore in 2018. Crime is much lower. How can we say which variable contributed in which amount?
> I'd be surprised if one could ever make such a statement.
"We found some cities where crack got big at different times but lead came at the same time"
"We found some cities where public housing declined at different times but lead came at the same time"
"We found some places where police surveillance..."
This is the aforementioned rabbit hole. People will have studied such evidence to various degrees.
But seriously, the point of this article is that studies still find a correlation between lead exposure and crime, after accounting for confounding.
And yet, that's not the same arguing that lead exposure was the only cause of the crime boom.
From one of the papers cited in the parent article:
"A growing body of evidence in the social and medical sciences traces high crime rates to high rates of lead exposure. Scholars have shown that lead exposure and crime are positively correlated using data on individuals, cities, counties, states, and nations. Reyes (2007) exploits state-specific reductions in lead exposure due to the Clean Air Act to estimate the effect of lead emissions from gasoline on violent crime. She reports that reductions in childhood lead exposure in the 1970s and 1980s accounted for more than half of the violent crime decline of the 1990s.2 Stretesky and Lynch (2001) estimate that, from 1989 to 1991, counties with air lead levels equivalent to .17 μg/m3 had homicide rates four times as high as counties with air lead levels equivalent to 0 μg/m3. Mielke and Zahran (2012) show that air lead and aggravated assault rates were strongly associated in a panel of U.S. cities. Longitudinal studies of individuals document a positive relationship between pre- and post-natal lead exposure and delinquency (Dietrich et al., 2001) and arrests for violent offenses (Wright et al., 2008). Cross-sectional research on individuals (Denno, 1990; Needleman et al., 1996, 2002) and counties (Stretesky and Lynch, 2004), studies using cross-national panel data (Nevin, 2007), and analyses of national time-series (Nevin, 2000) have yielded similar results."
Are each of these going to be able to factor for every possible confounder you can think of? No. But it's not like they aren't controlling for anything. That's the whole gist of the parent article - three studies using three new ways of controlling for other variables. Have you seen multitudes of studies that point to any of those other confounder you mention having better evidence, across time and geography, while controlling for lead and all the other possible confounders? Again, nobody is arguing that there are no other factors. And nobody has a precise answer on just how much, because it's impossible. But all studies point to: very large effects, still happening in some cases, and largely preventable: https://www.dropbox.com/s/07z65p9a5wdppfl/LifeAfterLead_AEJ_...
Aggressiveness like this will get you banned on HN. Please read https://news.ycombinator.com/newsguidelines.html and follow the rules when posting here.
> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.
> Please don't post shallow dismissals
But perhaps doing neither of them more "civilly"? I'm genuinely looking for guidance on handling of this thread, not trying to argue. Thanks.
You seem to agree with me that there are other contributing factors.
Now that we're both happy, I will thank you for the work you put into investigating the sources and bid you a very happy, unleaded farewell.
I think it's impossible to say how much any factor contributes in a quantitative manner. "36% of crimes were committed in high lead areas, whereas 23% of crimes were committed in high crack consumption neighborhoods"?
I think it's all a mish mash of variables and it's best not to pick apart too many strands of data.
One thing we can say for certain is that murders are down 50% since 1980 despite population in the USA doubling. That is an amazing achievement and I highly, highly doubt it was chiefly due to our generation not having lead in their blood.
On an anecdotal basis only, which sounds more plausible, then:
1) Murder rates are 4x lower chielfy/solely because of unleaded gas
or
2) Murder rates are 4x lower because of quite a few qualitative observations that we think data would confirm each played a role.
It's like saying, "I think murder rates are higher in Norway compared to Sweden not because of some big societal difference between the two countries, but probably because I remember a news story where a depraved lunatic shot 90 kids on an island."