
Predictive policing lacks accuracy tests - danso
https://www.muckrock.com/news/archives/2019/nov/05/predictive-policing-lacks-accuracy-tests/
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Barrin92
not only does it lack accuracy tests, it has been studied in the past, for
example by RAND¹ and there's no evidence that it works at all.

more importantly, it should be noted that these are essentially unproven
systems that are being beta tested on largely minority groups. That something
like this is happening in a country with a rule of law and at least in theory
constitutional safeguards is reprehensible.

[1][https://link.springer.com/article/10.1007/s11292-016-9272-0?...](https://link.springer.com/article/10.1007/s11292-016-9272-0?wt_mc=Affiliate.CommissionJunction.3.EPR1089.DeepLink)

~~~
capnrefsmmat
The study you link is of a very different kind of system: creating a list of
people considered likely to be victims of homicide or violent crime, and
trying to intercede.

PredPol, the system in the article, does _not_ do that. PredPol is primarily
about mapping crime in space, and trying to predict which regions of space are
most likely to have future crime. It doesn't focus on individuals in any way.

The people behind PredPol did run a randomized controlled field trial with
LAPD and claim to have found reductions in crime by directing patrols to
predicted hotspots [1]. Hotspots policing studies generally have found
reductions in crime when directing patrols to hotspots, or conducting targeted
interventions (like improving street lighting, talking to local businesses,
etc.). But I should note that running a good, well-controlled experiment of
something like policing is _very_ hard, so the quality of the evidence is not
exactly astounding.

 _However,_ there are indeed constitutional implications, as you note. For
example, if a model says an area is a "high crime area", police may be able to
use that as part of the justification for stop-and-frisk, reducing the need
for any individual suspicion or reason to search you. And, of course, there
are fairness problems: high-crime areas tend to be poor and minority areas,
and hotspots policing may harm trust in police (if they harass the residents
for petty offenses) and either lead to overpolicing or underreporting of
offenses.

I have a fairly thorough review of the literature on my website [2].

[1]
[https://www.tandfonline.com/doi/abs/10.1080/01621459.2015.10...](https://www.tandfonline.com/doi/abs/10.1080/01621459.2015.1077710)

[2] [https://www.refsmmat.com/notebooks/predictive-
policing.html](https://www.refsmmat.com/notebooks/predictive-policing.html)

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wry_discontent
It's pretty well known that increased policing doesn't decrease crime. These
are the same tactics in new clothes used to target PoC. Even if the ML is
_working properly_ the biased nature of the existing justice system is going
to cause it to target PoC disproportionately.

~~~
AlexTWithBeard
_target PoC disproportionately._

But what would be the purpose of it? Are you saying LAPD wants to put all
black people in cages and then enjoy life in a city made exclusively of white
(and chinese and indians)?

Or they simply enjoy being dickheads and stop-and-frisking people?

~~~
wry_discontent
I don't know what the purpose is. I can't speak to the intentions of anybody
involved, but the data are pretty clear. PoC are disproportionately stopped-
and-frisked, they're disproportionately brought to court for minor offenses,
disproportionately killed by police, and disproportionately sentenced,
relative to white defendants.

The why is an interesting thing to pursue, but I haven't seen a satisfactory
explanation of why. The what and how are more clear, though.

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martingoodson
'We have demonstrated that predictive policing of drug crimes results in
increasingly disproportionate policing of historically over‐policed
communities. Over‐policing imposes real costs on these communities. Increased
police scrutiny and surveillance have been linked to worsening mental and
physical health;and, in the extreme, additional police contact will create
additional opportunities for police violence in over‐policed areas.'

[https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-...](https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-9713.2016.00960.x)

~~~
AlexTWithBeard
_Increased police scrutiny and surveillance have been linked to worsening
mental and physical health_

I find it surprising. I would be happy to see more police in where I live. In
my layman's mind police, pretty much by definition, prevents and deters crime.
They may not be perfect in that, but in most cases they're fine.

~~~
mschuster91
> In my layman's mind police, pretty much by definition, prevents and deters
> crime.

That would be the case if police were adequately trained and equipped. However
US police forces on average (!!) are trained only for not even 9 months (per
[https://www.snopes.com/fact-check/police-training-
killings-u...](https://www.snopes.com/fact-check/police-training-killings-usa-
nordic/)), which means that there are likely cases in which only weeks of
training were given. German police, in contrast, train for two and a half /
three years (per
[https://de.wikipedia.org/wiki/Polizeiausbildung_in_Deutschla...](https://de.wikipedia.org/wiki/Polizeiausbildung_in_Deutschland)).

That, combined with a lack of hiring standards (e.g.
[https://www.portlandmercury.com/blogtown/2019/06/19/26671582...](https://www.portlandmercury.com/blogtown/2019/06/19/26671582/portland-
police-lower-officer-hiring-standards-to-address-poor-recruitment-rates))
leads to the perception of police being nothing more than paid thugs with a
uniform. The massive availability of guns as well as former military equipment
in police hands doesn't help either, quite to the contrary. When I have an
easy sledgehammer (=a tank and a gun), I'll shoot first and ask questions
later.

When it comes to "overpolicing", you also have to note that it's way easier to
arrest someone dealing/smoking cannabis on the street (mostly poor PoC)
compared to arresting a rich white banker who is snorting cocaine on his desk.

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excalibur
Why would they call it PredPol? Don't they get that this could be just as
easily interpreted as "Predatory Policing," which is quite likely more
accurate?

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thewhitetulip
I don't understand why this isn't obvious. Predictive analysis works if you
have correct set of data. DOJ is biased towards African Americans, their data
is skewed + you can't really predict what someone could do.we are humans and
not rule following robots.

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freen
Unless you are very careful, machine learning is the process of projecting the
biases of yesterday into the predictions of today.

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nroets
The alternative to a rule driven machine is human decision makers whose
emotions will play a role, sooner or later. (Prejudice and favouritism is just
two emotions that are bad in this case)

With a rule driven machine, the rules and be reviewed for any direct form of
prejudice and favouritism.

~~~
danso
We've already had rule-driven frameworks: three strikes and mandatory
minimums, the latter of which resulted in huge sentences for non-violent drug
offenses – particularly those involving crack, a drug more prevalent in black
communities, and for which the threshold to trigger a mandatory sentence was
1/100th that of powder cocaine: [https://www.aclu.org/other/cracks-
system-20-years-unjust-fed...](https://www.aclu.org/other/cracks-
system-20-years-unjust-federal-crack-cocaine-law)

~~~
AlexTWithBeard
That's something I never managed to understand: if I'm a black person, and I
know that current laws will unfairly publish me for drugs possession, and I
know that police tenderly loves to search me at any opportunity... Doesn't it
mean that I should stay as far as I can from crack and beg all my friends and
relatives to do the same?

~~~
danso
You could say that for any crime or malady of society, that it's confusing to
you why millions of fellow citizens have chosen something you've found easy
and obvious to avoid yourself. That doesn't address or excuse why one
variation is vastly disproportionately punished.

~~~
AlexTWithBeard
I understand your point, but it's not about "any crime", it's about a very
specific variation of a crime. Imagine DUI having a much more severe
punishment and zero tolerance limits if the driver was caught between 10pm and
11pm. Now, it's 10:30pm and you've just had half a pint of beer. You need to
drive back home. What do you do? Heck, you wait half an hour! Will it decrease
total DUI? No. But 10pm to 11pm will be the safest time in the streets.

Poisoning your spouse now leads to a mandatory death penalty? Good. Now you'll
just strangle her.

A gang is defined as 5 people or more? Excellent. All robberies are now
performed by strictly no more than 4.99 people.

Crack is being cracked down upon? Fantastic. We'll smoke
weed/tobacco/soap/whatever.

When there is an alternative, not using it is just dumb.

