> It’s an intriguing idea — particularly since we don’t have a better explanation for the big changes in crime rates during this period.
Did not freakanomics come up with a famous (and to me more convincing) argument that it legalized abortion was the reason for the drop in crime? At they very least it dispels the arguments we don't have a better explanation and doesn't even mention it.
Both the lead and the abortion hypotheses could be true. In fact they could both be true AND the papers indicating one explanation could conceivably throw out the other explanation. If you're interested in one hypothesis, you might not spend the time going through alternatives as thoroughly as someone investigating the other.
Looking specifically, the studies are always trying to isolate some effect, often using some sort of clever control derived from the proposed mechanism. So in this case there's a paper that points out how lead only goes into the water if the water is acidic, and they look at places with non-acidic water or non-lead pipes to control. For abortion, it's been a while since I read it, but there would be something along the lines of when abortion became widespread in a given community. You'd then look at differences in frequency and think about whether that came out in the crime stats when the kids got older.
The rabbit hole is where you can come up with ever more interesting corollaries and data that support or do not support some hypothesis. You see this across the social sciences all the time. There's also confounding problems, say you know people tend to move to the city when they grow up (I don't know if this is true), then how valid is your birth -> crime data?
Here's a load of random observations I thought up:
- If abortion is the key, why do crime rates keep falling? Why is it not a step effect?
- If it's lead, did crime rates increase 20 years after leaded fuel became a thing?
- What if it's abortion AND lead? There are countries where abortion and lead are timed differently, how about looking at them?
- What if it's neither, but both are caused by some other thing? Say economic development -> both?
Yes. The rise and fall of violent crime rates correlate very tightly to the rise and fall of leaded fuel, with a ~20 year gap. You see the same correlations in different countries that had different phase in / phase out times, and different U.S. states that had different timelines. (E.g. if a state phased out leaded gas 5 years earlier than average, their crime wave also started abating 5 years earlier than average)
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
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."
See this link for the argument.
Edit: also the original lead argument pretty hinges on a single moment of crime increase. I don't see how more detailed studies of the correlation could be more revealing since reality only provides one instance of a potential to leaded gasoline and reality is going to be noisy.
Re: your second point, one of the three studies in the parent article looks at city level crime in the 1920s/30s using city piping infrastructure (lead vs. iron) for test/control groups. The leaded fuel was a substantial source of increased lead levels but not the only one.
Without stating which explanation is correct (which is impossible to prove). We can easily disprove the statement that no other explanations exist though.
I'm not saying abortion is the ONLY factor, just that if it is, you'd see a step (or sigmoid) in the crime data and then that's it. As in there's a constant density of abortion sensitive criminals until they get aborted.
Similarly if abortion became illegal again, you'd see a step the other way. I'm not familiar with it, but I've heard it's gotten very hard in some places in the US to get an abortion.
The lead mechanism is also easier to validate. Simply correlating the drop in crime with Roe v. Wade plus 20 years isn't enough--you also have to show some evidence which mothers and families demographically tend to produce more criminal children, and that these same mothers and families disproportionately chose abortion in greater rates after Roe v. Wade.
I don't think that's a correct explanation of their position.
Instead, children born who would have been aborted if it were legally available are more likely to be born into environments that lead to increased propensity to criminal behavior: poverty, no father figure, poor supervision, etc.
- 1) Observe correlation in sample.
- 2) Propose explanation for correlation
- 3) Take new sample.
- 4) See correlation still holds, therefore propose that explanation is the reason.
Of course the thing that should be clear in that process is that the explanation is irrelevant. The explanation could well be 'because 1+1=3.' There's an insufficient amount of attention directed towards falsification, prediction, and experimentation that's more than 'toy studies' or abstractly related. In many cases there are reasons for the lack of these processes (ethical concerns, time constraints, unavailability of an appropriate sample, etc) but those reasons do not change the fact that without these processes, the 'science' provided by the above sort of logic is not science - it's just plain old fashioned speculation in a fancy suit.
The sprinkler being on may be getting the grass wet. But the sprinkler being on does not mean that it isn't raining.
There was a bug in Donohue and Levitt's code which, combined with other factors, makes the effect go away, supposedly:
- why did the crime rates simultaneously drop in states where abortion was already legal before Roe v Wade?
- why did crime rates have a similar drop in similar time frames in other countries regardless of the legality of abortion?
There is a very strong correlation between the banning of leaded petrol and reduction in crime rates around the world.
Reuters has been doing incredible investigative journalism: https://www.reuters.com/investigates/special-report/usa-lead...
The abortion theory makes intuitive sense, but as far as I know it hasn't been studied as rigorously.
It isn't a better one than lead. It was one of many correlated events. It was an interesting theory when it came out, but I don't think anyone takes the abortion argument seriously today since both abortion rates and crime rates have fallen together for nearly 40 years. Even when freakonomics came out, I remember my economics professor saying it was used to sell books.
Also, if the freakonomics theory was valid, the legalization and widespread use of birth control ( which prevented far more pregnancies and births ), not abortion, should be getting the credit. You are comparing an ocean ( birth control ) with a small pond ( abortion ).
The abortion theory is pretty much debunked now. That's why you don't hear about it anymore.
It's most likely a confluence of events that has led to drop in crime rates. Birth control, less lead, more TV/internet/etc, longer education period and changes in the law or prosecutions. At the end of the day, nobody really knows what caused the decline in crime for certain. Abortion sells a lot of books and gets a lot of media support/press, but the continuing decline of both abortion rates and crime rates seems to indicate that abortion isn't the cause.
Which is why it's important to look at actual data and try to keep an open mind. This stuff is complicated!
The ecosystem is driven by demand from the US, and Mexico has the supply. The brutality is a consequence of a power struggle to control those resources.
How can you on the one hand so easily dismiss the evidence that lead causes violence, which is backed up by rigorous statistical analysis and medical evidence, and on the other hand assert so surely that you know the answer?
If you were consistent, surely you'd apply skepticism to your own explanations as well.
Violence is caused by multiple factors. One additional factor is the billions of dollars to be made preparing and running drugs from Mexico to the US.
My assertion is that if lead were removed as a factor, this would not negate the other cause.
They're entirely aware that they're killing people and have openly said in management meetings that they won't stop manufacturing the product until government regulation forces them to.
Mind you, lead levels don't only increase in the country the chemical is used; it moves through entire ecosystems and across oceans. Lead levels don't fall to below dangerous levels for decades. This isn't just poisoning the people nearby; it's poisoning the entire world in small, insidious ways. And chemical companies are profiting from that. The margin they're selling TEL for would make government contractors cry.
And to top it off, they have virtually no quality program surrounding their products because they don't need one; all of their deals are done with backroom handshakes and agreeing to take the blame if an issue arises. Their company is built around the idea that it actually costs less to just say "Yeah, we're terrible people, fine us" than to actually try and comply with government regulation. They've repeatedly been caught in corruption and environmental probes, and have changed their names in the states and in the UK multiple times. They were literally caught trying to bribe their way into selling TEL in Iran. 
Article is pretty low quality.
There's a small airfield near here; 20 years ago it was surrounded with orange groves and an old defense contractor plant, and now they're putting in $800,000 McMansions less than 1km away.
Note the the linked study did not consider wind patterns. Other studies cited in that one suggest that wind matters a lot, with someone downwind by a given distance getting a higher exposure than someone upwind the same distance.
No one has been able to find a practical replacement anti-knock compound, and apparently it’s been decided that the safety tradeoff is worth it (slightly poisoning the atmosphere vs. risk of in-flight engine failures).
G100UL is flying in some experimental aircraft today. (These include originally factory-built airplanes/engines converted to experimental use for the purpose of this testing.)
It’s probably 5+ years away in the very best case, as there’s a science/engineering problem to clear, but then an even larger regulatory hurdle remaining to clear, as the majority of avgas sold today is sold for airplanes only certified to run on 100LL, so there’s a certification change needed at some level. If that doesn’t apply to the whole fleet, it’s a logistics nightmare for airport fuel vendors.
Disclaimer: I casually know one of the principals at GAMI and have visited their test lab. I have no financial connection to them, however. I want them (or anyone else with an all-fleet solution) to succeed so that I can stop burning leaded avgas.
The Cirrus factory turbos are low compression engines (7.5:1). That gives a greater margin against detonation (at the cost of efficiency). That won’t extend to 8.5:1 compression, big-bore engines near as easily, whether turbo or normally aspirated. (This also means that I doubt it will work in the Tornado Alley turbo-normalized Cirrus.)
I too want to get the lead out of my life, especially since my kids fly in the airplane and are going to have exposure to it incidentally, even as I try to minimize it. It may well end being faster to just make more money and switch to Jet-A than to wait for a viable unleaded fuel to take over the market.
Like if you wanted to make a safety tradeoff you'd just ban general aviation (Imagine, they poison everyone a little bit, by taking pretty high personal risks).
There is a lot of money going into replacement engines but they're mostly diesel since the most dominant fuel in aviation is Jet-A (essentially diesel/kerosene). These have found some success in Europe where 100LL is much more expensive as the operating costs of the diesels is much greater given their complexity, maintenance needs, and initial acquisition costs.
Many more people are killed by dog bites in America than ground GA fatalities (turbine and piston combined). I’d no sooner make a safety argument to ban dogs than piston airplanes.
It looks like crashes result in about 300 annual deaths (of people on the planes) and dog bites 20 or 30.
It seems that flying in a small plane is only somewhat more dangerous than driving the similar distance. But driving isn't really safe in the US either.
It didn’t occur to me (or seemingly Wild182) that you were suggesting banning an activity that was risky essentially solely to the participants in that activity. Being worried about ground fatalities of non-participant is something that makes sense, so that was the line of reasoning I thought you were suggesting. It was my mistake.
On a per-mile basis, light aircraft are approximately as safe/dangerous as motorcycles. That’s the “all causes” rate for both. Both activities have means to substantially reduce the risk versus the “all causes”. On a cycle, wear a helmet, drive within your limits, don’t drink and ride. In an airplane, don’t run out of gas, don’t fly into thunderstorms, don’t fly in clouds if you’re not instrument rated and current.
I guess "individual" would follow your understanding somewhat better?
I misread, making insufficient allowance for the concern to regulate risk taking by others.
Microprocessor production is toxic. Should we ban microprocessors? Dry cleaning is notorious. Should we ban dry cleaning? Gasoline is toxic in all forms. Should we ban gasoline? Batteries are almost always toxic. Should we ban batteries? Or maybe we should just let the EPA and similar government bodies regulate this, along with the courts, which means we’re all good today.
5 North Korea
Also I found this: https://www.motherjones.com/kevin-drum/2016/12/prediction-te...
Very interesting indeed.
I am hoping you are not attributing violence and instability in some of these countries to lead based gasoline. Sure, there may be correlation, but these places are centuries old. There are many factors like culture, religiosity, socio-economic status , history, contemporary culture, so on and so forth.
Before there were studies like the ones mentioned in the article people wouldn't believe it for cities like Flint in the states neither. I’m still not 100% convinced that there is causation. But if those studies are no fakes and hold up for repetition then I’d argue that there is some truth behind the theory
Yes, unless you have a secret way of ruling out the other much more likely factors (i.e what GP mentioned).
You could argue that those countries still use leaded gasoline because the political turmoil/violence within them makes folks prefer the cheaper, easier fuel to produce.
I wonder what fraction of TEL consumption worldwide is due to aviation vs. these few remaining countries that use it in motor gasoline?
It seems plausible that high environmental lead levels contribute (with at least a small effect size) to violence and crime.
If a lead-free environment is already violent and insecure, would you expect adding environmental lead to make it less violent, more violent, or the same?
Lead affects impulse control and could be a factor in certain civil phenomena. It's easier to whip up a mob when there's a lot of lead poisoning.
Different states introduced and subsequently banned leaded gasoline on different schedules, so this was a 'natural' experiment, unless you can think of some other causative factor that precisely explains the timing of the rise and fall of crime.
I don't understand this content-free 'correlation does not equal causation' argument.
Sure, in the absence of other evidence and a mechanism of action, we should have healthy skepticism, but it's known how lead affects brain development, particularly how it screws up development of the frontal cortex, lowering both intelligence and social inhibition.
Did they also account for changes in how crime rates are reported over time?
One would have to account for hundreds of different variables before you could ever conclusively prove a connection between lead and crime.
The Bureau of Justice Statistics conducts a yearly survey asking people about the crimes they were a victim of in the past year regardless if the crimes were reported. The Bureau of Justice survey shows a much more dramatic reduction in crime than if you just look at reported crimes.
>Using the FBI numbers, the violent crime rate fell 48% between 1993 and 2016. Using the BJS data, the rate fell 74% during that span.
It's been done before by people with more credibility than a message board user.
The effect of lead residuals on brain is pretty well known..
I like the trick to select a control group by acidity in the water.
So your point is?
"Lead exposure in childhood linked to lower IQ, lower status jobs, as adults"
Which also correlates with criminality.
The second study finds that distance to roads correlates with lead exposure. They do discuss relative contribution from multiple sources: flaking indoor lead-based paint, lead in soil around foundations (from maintenance of outdoor lead-based paint), and roadside lead.
Young people burning cars in Paris suburbs around 2010 may not be technically violent crime but it's pretty weird and special. And also in decline:
I know there's no known level of safe lead exposure, but I don't have a good sense from a cost benefit perspective of how much to do to try to lower my exposure.
Imho one of the more infamous and recent examples of human hubris. Who knows what we are downplaying right now, that might end up really messing us up in another couple of decades? Only time will tell.
It's the correlation with crime specifically that is the interesting part.
Some countries have banned lead even before the US, but crime rates are still growing(Brazil, for instance). Poverty alone does not explain this. There are countries just as poor (or more), with corrupt police forces and that do not have the same issue with violence.
I wouldn't be surprised if the lead is the cause of both.