Vsauce!
Kevin here -- with a PERFECT explanation for a 56% reduction in violent crime between 1992
and 2002.
A study of Uniform Crime Reporting data found that removing lead from gasoline over a decade
before reduced lead's detrimental effects on children's developing brains -- so when
they grew up, they committed less crime.
Makes sense, right?
WRONG -- using the Bureau of Justice Statistics National Crime Victimization Survey data showed
that leaded gasoline had...
no effect at all on violent crime rates.
It wasn’t 56%, it was ZERO percent.
Two data sets led to 2 completely OPPOSITE conclusions -- because measuring social phenomena
is hard.
And it's actually a really new thing -- 200 years ago, no one even measured crime rates.
Now we measure everything.
The problem is that most of our measurements…
are wrong.
We’ve been counting people for a while -- China had censuses over 4,000 years ago, the Romans
conducted censuses for taxation and military conscription -- “censere” in Latin literally
means “to tax” -- and William the Conqueror ordered The Domesday Book to be compiled in
1086 -- but even then it was just counting people, property, and farm animals.
There was nothing about people’s lives -- let alone keeping track of what they did to harm
others.
Democracy had matured by the 5th century BC in Athens, but demography didn’t exist until
the 1600’s.
English haberdashier John Graunt analyzed the weekly “Bills of Mortality” -- official
lists of births, deaths, and causes of death -- to better understand life in the 1660’s.
170 years later, Andre-Michel Guerry changed everything.
His 1832 presentation to the French Academy of Sciences detailed the “moral statistics
of France” -- assaults, murders, suicides, Guerry tracked them all, revealing that their
rates differed throughout France and by age, sex, race and the other general demographics
we still use.
There were some odd findings -- like literacy rates weren’t correlated with crimes against
people, while higher literacy rates were correlated with crimes against property.
Apparently, reading makes you break things.
And Math had finally collided with morality.
The social statistics era boomed.
Some people wanted to lock up more criminals.
Others wanted to spend more money on social services they thought would reduce crime.
DOES THIS SOUND FAMILIAR?
Guerry proclaimed, “We are forced to recognize that the facts of the moral order are subject,
like those of the physical order, to invariable laws.”
The truth is that crime statistics are HIGHLY variable.
Highly.
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Okay.
The first problem is uniformity -- in police forces, in data collection, and in laws.
Cool.
WHAT DOES THAT MEAN?
Here’s an example:
Let’s say the rate of assault annually is 1,655 per 100,000 in Scotland, 23 in India,
and 291 in Estonia.
Is a Scottish guy just 70 times more likely to punch you in the face than an Indian?
Are Estonians relatively well-behaved?
Let’s analyze the data.
Scotland has a well publicized alcoholism epidemic and alcohol is a frequent component
of assaults.
Scotland consumes 9.4 liters of pure alcohol per adult every year, and India consumes just
5.7 liters.
So it would make sense that Scotland would have a lot more assaults -- which was a major
argument by the teetotaler movement and Prohibition.
But Estonia consumes 11.6 liters per adult annually, and their assault numbers are way
lower than Scotland’s, so… it’s more complex than this.
Maybe it’s more police.
Scotland has 318 per 100,000 residents.
India has just 152 -- so less policing might mean fewer reported crimes.
Is it just easier to get caught and held responsible in Scotland?
Estonia has 336 police per 100k, which is a little more than Scotland.
So… does that additional 5.6% of police presence make a huge difference in deterring
assaults?
I doubt it.
This has to be a question of laws.
Maybe Scotland’s assault laws are so loosely defined that their rate is artificially inflated.
Well… no.
Scottish law considers assault to be an act that causes bodily harm or leads one to think
bodily harm is imminent, which is pretty sensible.
Are India’s definitions of assault so narrowly-defined and severely restricted that hardly anything
qualifies?
It’s actually the complete opposite -- Section 351 of The Indian Penal Code has such a broad
definition that it includes shaking your fist in a threatening manner!
So, what’s the answer here?
Do the Scottish just report everything to the police?
Do Indians handle fist-shaking problems themselves, so police never even know about the crimes?
Maybe Estonia is obsessive about crime tracking and the Indians are a decade behind on their
paperwork.
Who knows?!
This is the problem with “moral statistics” -- what looks like an apples to apples comparison
can be apples to aardvarks.
The second problem is data can change over time.
In Boston, the Cambridge-Somerville Youth Study was conducted in 1945.
It went like this.
253 pairs of boys were matched by age, IQ, and a range of social factors.
Researchers flipped a coin to see which of the 2 would receive counseling, tutoring for
school, and even a summer camp getaway.
The idea was that delivering all those social supports would improve their life’s outcomes.
The research showed it didn’t really do anything.
30 years later, a researcher followed up the lives of all the boys involved in the study
-- and found that the ones who received counseling committed MORE crime and had higher rates
of alcoholism and mental illness.
Which is PRETTY WEIRD.
The third problem is money -- you’ve got to show results to keep your jobs and your
funding -- that perverse incentive seems to have led the LAPD to misclassify 1,200 violent
crimes as minor offenses in 2012-2013 to reduce its crime rate on paper.
That same year, Chicago Police Department erased murders from official crime statistics
once they realized they wouldn’t be able to solve them.
In 1946, criminology professor Paul Tappan wrote that we “study the criminals convicted
by the courts,” and “not the real criminal at all” -- but an insignificant proportion
of non-representative and stupid unfortunates who happened to become enmeshed in technical
legal difficulties.”
And that’s the fourth problem -- a significant portion of crimes go unreported, and many
of the major criminals go free while their foot soldiers get caught.
But even when we know a crime has happened and who’s responsible, we’d struggle to
know why.
Is there correlation?
Is there causation?
Does a decrease in crime reflect a new law being effective or better policing, or is
it a statistical mirage caused by a regression to the mean -- or some social factor no one
has even considered?
And what are the unintended consequences of our interventions?
The fifth problem is that the media reports the numbers it’s got -- and sometimes the
numbers it’s incentivized to report, which can lead to media-generated crime waves and
moral panics.
Crime rates affect property values, where people choose to live, what schools their
kids attend.
They determine where we as a society assign blame, and they can infect our social attitudes.
Our perception of crime -- sometimes too strong, sometimes too light -- informs who we elect
to lead and write laws for towns, cities, states, and nations.
The final problem is... you.
Did you ever do something bad as a kid, and when your mom asked you, “Why did you do
it?”
you said, “I don’t know” -- and you really, truly did not know?
It’s the same with criminology -- there’s such a complex relationship of psychological,
biological, social, emotional, and economic factors that even when it’s happening in
our own heads, we usually can’t make any sense of it.
So if we can’t trust the numbers and we can’t trust ourselves…
what are we left with?
Knowing that we don’t know is probably a good place to start.
And as always, thanks for watching.