
The wear patterns of jeans aren’t good forensic evidence - Tomte
https://arstechnica.com/science/2020/02/the-wear-patterns-of-your-jeans-arent-good-forensic-evidence/
======
ip26
A false positive rate of 0.1% and a false negative rate of 40-50%? Isn't
that... actually pretty useful? You'd never want to convict someone based
exclusively on this, but it could fit into the "preponderance of evidence"
standard. No one piece of evidence is foolproof, e.g. the classic examples of
DNA & fingerprints- did you even lift the right set of prints or collect the
right sample of hair?

~~~
burkaman
I'm not sure the article correctly interpreted the findings. The paper is
here:
[https://www.pnas.org/content/pnas/early/2020/02/18/191722211...](https://www.pnas.org/content/pnas/early/2020/02/18/1917222117.full.pdf)

What they found was a correlation between false positive rates and true
positive rates, where IF you could accept a false positive rate of 0.1%, THEN
you could get a little over 50% true positive rate with the longest seam
length under "ideal imaging conditions".

They do not attempt to estimate the false positive rate of whatever
methodology FBI agents are using in practice. I doubt the FBI has a rigorous
well-defined test that could be analyzed; I suspect this is just a general
technique that is applied by different agents in different ways.

Even if the FBI's methods approach this ideal false positive rate (which they
can't), they are not describing it honestly in court.

> When, for example, an FBI analyst identified the plaid shirt in a
> surveillance video as that belonging to Wilbert McKreith, the analyst stated
> in court that the odds that two different shirts would match were a
> staggering 1-in-650 billion. The analyst arrived at this number by making
> eight measurements along two seams, estimating the probability that the
> plaid stripes at these eight locations were misaligned by a certain
> distance, and then multiplying all eight of these probabilities to reach the
> astronom-ically low odds of 1-in-650 billion.

------
avs733
For a broader discussion of just how bad, and dangerous, forensic sciecne can
be there is a Scientific American article [0] from about 5 years ago. Along
with many others if you take a look. Most access this issue through one
specific case that is of local relevance...but at a high level, people have
literally been executed based on bluntly fake science and courts opt out of
doing anything.

If AAAS is telling you your field is bad at science, everyone should situp and
listen [1]. For example...there are no scientific standards around
fingerprinting.

[0] [https://www.scientificamerican.com/article/can-we-trust-
crim...](https://www.scientificamerican.com/article/can-we-trust-crime-
forensics/)

[1] [https://www.aaas.org/resources/forensic-science-
assessments-...](https://www.aaas.org/resources/forensic-science-assessments-
quality-and-gap-analysis)

~~~
duxup
There was a PBS show that looked into how wonky forensic science could be.

A common certification at the time was earned by taking an online class and
answering multiple choice questions ... and blamo you had a certificate that
they found on a lot of resumes. It didn't require much of any actual
scientific knowledge.

~~~
thaumaturgy
This appears to be surprisingly common in both law and fire. I hold a handful
of such certificates, all of which say I'm qualified to do things I'm mostly
certainly not.

I'm trying to change this behavior by incorporating objective examinations
into one of my specializations and it's extremely difficult.

~~~
Agenttin
I wouldn't mind tacking some BS certifications onto my resume, which would you
recommend?

~~~
thaumaturgy
In all seriousness, the FEMA ICS 100 and 200 courses:

100:
[https://training.fema.gov/is/courseoverview.aspx?code=IS-100...](https://training.fema.gov/is/courseoverview.aspx?code=IS-100.c)

200:
[https://training.fema.gov/is/courseoverview.aspx?code=IS-200...](https://training.fema.gov/is/courseoverview.aspx?code=IS-200.c)

They are both available online for free and you download a little certificate
afterward.

ICS is the Incident Command System used by law, fire, and other agencies to
manage "incidents" \-- anything from, "my kid just disappeared from my front
yard" to "the entire town of Paradise just burned to the ground, now what do
we do?"

There are some principles in ICS that any technical manager should find
helpful. Someday I'd like to write a long article on what technical managers
can learn from ICS, but in the meantime I'm happy to suggest other people just
take the first two courses.

------
wheaties
More junk science used to convict people in the courts of America? I'm going
to die now of not surprise! I guess a better way to say this is, how does the
proliferation of shit work like this happen so fast but the refutation take so
damned long?

~~~
SaberTail
There's an asymmetry to the process of how judges allow evidence.

If one judge somewhere allows a prosecutor to present junk science as
evidence, that becomes precedent that other prosecutors can point to in order
to convince other judges to allow it, too.

Once precedent is established, it takes the decision of a higher court to stop
use of that junk science. It takes time for cases to work their way up.

~~~
Mirioron
At what point are judges liable here? They play a vital role in our society
yet a lot of what they do seems to be based on precedent established on a
whim.

~~~
SllX
Under the Appeals process.

If you mean criminally liable though, we don’t hold them liable for the same
reasons we don’t hold lawyers criminally liable for defending a convicted
criminal. At the end of every human process, you need someone somewhere to
exercise some human judgement and be able to rely on it. Humans are not
infallible though, and neither is anything else we create whether it’s court
systems or computer systems.

This is one of the reason’s why we have trials by Jury in cases where life,
limb and liberty are at stake. It is one thing to convince one person, the
judge presiding over the case to pass judgement one way or another, but a
whole other thing to convince several of your peers of equal social standing
to pass judgement. It’s still not perfect, but nothing ever will be.

~~~
Mirioron
Do judges lose their jobs after successful appeals? I'm sure it has happened,
but this seems like an incredibly rare event. Yet lawyers who do their jobs
poorly (even ones defending criminals) can get fired from being a lawyer and
have consequences on their ability to practice law. For most jobs, if you do
it poorly enough then there can be severe consequences that follow. Yet here
there are matters of life and death at play and nobody seems to have any
responsibility in their screw up. Even police officers are held accountable
when great harm comes to the innocent due to what they did.

~~~
SllX
Federally, Article III judges can be impeached and removed by Congress.
Administrative and Military (Article II) judges can be fired outright or
demoted. State-level, depends on the State, but in California we have
something called retention elections, which rarely result in a change in
office, but changes in office have come about after particularly unpopular
rulings.

An appeal doesn’t directly lead to jobs loss, but it doesn’t look good on your
record when your judgements are regularly overturned, particularly if you
aspire to a better position. Keeping your job isn’t always the only, or most
important incentive if you have any kind of ambition or want to leave any kind
of lasting legacy.

------
ARandomerDude
Link to the paper:

[https://www.pnas.org/content/pnas/early/2020/02/18/191722211...](https://www.pnas.org/content/pnas/early/2020/02/18/1917222117.full.pdf)

------
Rafuino
Most forensic science is complete BS. Very little has changed since the
pivotal National Academies of Sciences report, "Strengthening Forensic Science
in the United States" came out in 2009.

------
Cactus2018
[https://www.wired.com/1998/04/fbi-tracks-the-denim-
trail/](https://www.wired.com/1998/04/fbi-tracks-the-denim-trail/)

> (1998) FBI scientists reported at the American Academy of Forensic Sciences
> in February that they are using a new technique to identify criminals –
> analyzing the unique wear patterns of denim jeans and comparing them to
> photographs taken from crime scenes.

------
brohee
Bad forensic science kills : see e.g.
[https://en.wikipedia.org/wiki/Cameron_Todd_Willingham](https://en.wikipedia.org/wiki/Cameron_Todd_Willingham)

Executed following a conviction based on the worst junk science.

(there was no crime, everything pointing to a tragic accident)

~~~
ARandomerDude
> there was no crime, everything pointing to a tragic accident

From just reading the Wiki article (key caveat), I would say the case is not
"beyond reasonable doubt" thus a conviction is unwarranted. But that doesn't
mean _everything_ points to a tragic incident. This is a pretty murky case.

~~~
fsh
Is there a single piece of evidence for arson in this case? I don't see any in
the wiki article.

House fires happen a lot. According to the NFPA, in the US there were on
average around 350000 house fires per year between 2013 and 2017, 92% of them
accidental: [https://www.nfpa.org/News-and-Research/Data-research-and-
too...](https://www.nfpa.org/News-and-Research/Data-research-and-
tools/Building-and-Life-Safety/Home-Structure-Fires)

------
jpindar
I'm surprised that surveillance camera resolution is high enough to see that
pattern.

------
bryanrasmussen
I posted on ProPublica article earlier
[https://news.ycombinator.com/item?id=22430735](https://news.ycombinator.com/item?id=22430735)

------
woliveirajr
TL;DR: the "wear" pattern are those light/dark marks on both sides of pants,
along the seam, that would be "unique" to each jeans isn't enough to give a
"true positive" identification keeping the "false positives" low enough.

