

FBI notifies crime labs of errors used in DNA match calculations since 1999 - uxhacker
http://www.washingtonpost.com/local/crime/fbi-notifies-crime-labs-of-errors-used-in-dna-match-calculations-since-1999/2015/05/29/f04234fc-0591-11e5-8bda-c7b4e9a8f7ac_story.html?hpid=z3

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jmnicolas
"The public puts so much faith in DNA testing that it makes it especially
important to make those the best estimates possible"

The public was made to believe DNA testing was absolutely bomb proof, there
are even entire TV shows centered around this "fact" (CSI whatever ...)

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veb
What I found weird while reading this article was that they all said the
results would be "nominal" and nothing will realistically change regardless of
if the DNA tests were actually erroneous.

Uhhhh what? If people were sentenced for a crime based on the fact that their
DNA matched with the DNA found at the scene of the crime they supposedly
committed, then surely there's a massive problem here? Just _one_ case of this
would mean an innocent person has been rotting away in prison for the last
decade... and it won't just be one case!

I'm confused as to why they're not thinking this is a big deal.

You're completely correct when you say the public was made to believe DNA
testing was completely foolproof. If you're in court, being prosecuted and
they prosecution says that the DNA matches yours everyone instantly thinks you
are in fact guilty. If you've got a jury they'd all think the same too.

I thnk this is a really big deal, but I'm not in the US so I may be missing
something (again). :-)

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tbrake
> If people were sentenced for a crime based on the fact that their DNA
> matched with the DNA found at the scene of the crime they supposedly
> committed, then surely there's a massive problem here?

I get the impression - though I don't have the data/numbers obviously - that
in almost all of those cases the DNA evidence was being used as the cherry on
top of the evidence sundae they had already compiled.

That's why it won't realistically change much; either very few or none at all
are convicted _only_ because their dna happened to be found at a crime scene.

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bilbo0s
"... in almost all of those cases the DNA evidence was being used as the
cherry on top of the evidence sundae they had already compiled..."

Not to put too fine a point on it...

but that's the whole problem DNA was supposed to solve. Cases like rape X,
where all of the evidence pointed to guy A. Then we test a known serial
rapist, guy B, 30 years later to find out that he actually committed rape X.
The Innocence Project sails in, and in due course guy A is exonerated and sent
on his way after having spent 31 years in prison. We're stuck with a sizable
financial liability to the ex-prisoner. And for some reason, everyone calls
this a happy ending ???

DNA was supposed to protect us from situations like that. But now you say that
the evidence against guy A in rape X really would have been enough in any
case... so we shouldn't read too much into the fact that the DNA samples don't
match ???

I'm just confused as to what evidence would EVER prove guy A's innocence in
such a system ???

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tbrake
I was responding to a specific interpretation of OP's post which, upon
reflection, might not have been the best reading. In short: are people
convicted based solely on the presence of their DNA at a scene.

The way I read it was if it was being used in a frivolous manner, e.g. "There
was a murder in Times Square last night. We found a hair of yours in Times
Square. Case closed." Obviously there are more serious uses, and clearly a
spectrum exists of how important the evidence is in the case.

If, in the cases spoken of in the article, DNA evidence was used as the
strongest piece of evidence to get a conviction, then obviously that matters.
I didn't mean to imply it didn't.

But if, in the cases spoken of in the article, the DNA evidence was incidental
to a lot of other evidence - note this was the scenario I was responding to -
and not necessarily enough to convict on its own, and more of the "cherry on
top", then I agree with them that it might not change much in the way of these
cases.

We won't know what percentage fit either description until they've gone
through them.

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AnthonyMouse
> The way I read it was if it was being used in a frivolous manner, e.g.
> "There was a murder in Times Square last night. We found a hair of yours in
> Times Square. Case closed."

There will _always_ be more evidence than that. You can find circumstantial
"evidence" of anything. If you were friends with the victim then "the
defendant knew the victim." If you were enemies or competitors then you had
motive. If you had never met the victim but the victim was robbed then you had
motive again, and the same if you ever expressed opposition to any class of
activity the victim had ever engaged in. If you were caught on surveillance
near where the crime was committed then it will be used against you, but if
you were at home sleeping then you have no alibi. And so it goes.

A prosecutor can whittle the world of facts about your life down to only the
ones that imply you might have committed the crime. None of that stuff
actually proves anything -- but it sure makes a good show for the jury.

Throw fraudulent DNA evidence on top of it and the outcome is predictable.

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jimrandomh
This article is about errors in a set of population priors used in software.
That could affect the outcome of tests, but it also might not. However, given
that the FBI was recently caught having faked an entire field of forensic
science (hair analysis), there is little reason to extend them the benefit of
doubt.

The important question is: are these crime labs routinely processing control
samples, and if so, are they misclassifying any of the control samples?

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kiba
There is a difference between purposefully faking an entire field of science
and believing in pseudoscience and not being skeptical.

The effect is the same, either way.

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rasz_pl
>and believing in pseudoscience

lie detectors are a big thing for FBI

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meowface
Polygraphs? They know full well polygraphs are not "lie detectors". And a lot
of the general population knows that too. They're still useful when recruiting
candidates. Obviously their results are not admissible in criminal cases.

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veb
I know in New Zealand, you've got the right to redo tests with whoever you
want (i.e. private labs).

So, if the prosecution has said that your DNA was found at the scene or
something, you can then get that test done privately (yes it'll cost money) to
see if it matches up. You can do this as many times, with as many labs as you
need.

Is this a normal thing in the US too? I'm _assuming_ it is. If my assumption
is correct, then wouldn't another lab doing the same test come to a different
conclusion?

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hobs
Do you have to pay for the tests with your own money? If so, doesnt matter,
rich people dont need the extra help,and poor people cant afford it.

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veb
It's not that expensive. About $500 NZD for a basic test. Yes, expensive if
you don't have $500 but there's many ways to go about it: ask for invoice, get
legal aid to pay, do it through lawyer (who adds to their bill), hope you
still have family who loves you or friends.

Alternatively, you can make the court do it to rule out any problems. Most of
the time the labs come up with the same result but the courts are more than
happy to make sure it's about water tight.

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bane
It kind of makes me think/wonder that in criminal cases perhaps forensic
biometrics work should be done by two or more labs (maybe using two different
methods) to help cross-validate the results. My understanding is that most of
this work happens in a single lab under one test, so contamination or
procedural problems go unchecked.

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UnoriginalGuy
Maybe the same lab shouldn't even be testing both samples. Just send the
sample from the victim to lab #A and same from the accused to lab #B and
compare the digital results.

The two samples shouldn't be sent in together, there is absolutely no benefit
in that. Plus the lab shouldn't know what they're testing so there can be no
accusations of bias/manipulation (e.g. "this person is definitely a child
rapist, if you guys find this DNA matches this child rapist goes to jail, if
it doesn't' (wink wink) then they go free").

The anonymous digital results can then be shipped to the defence so that they
can double-check the degree of similarity with an expert of their own.

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bane
I see where you're coming from, but I'd be concerned if one of the labs has a
broken process somewhere (or contaminates the sample) that it would produce a
false negative and a possible match would not be found -- thereby leaving a
bad person out in the wild.

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mattstreet
I'd rather a false negative than a false positive. Too many people already
feel they can't call the cops as it is when they truly need help.

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falcolas
Just goes to show that humans can even mess up "perfect" evidence. How many
convictions will get overturned by this, I wonder. A factor of 10 is pretty
large, if they're talking about "1 in 180" levels of probability.

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throwawayaway
I wonder if innocent men are rotting away in jail that have given up
themselves and been given up on. They know they are innocent but I doubt 'the
system' will swoop down and fight for them.

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smeyer
I'm not sure if you are being rhetorical, but in case you aren't, such people
most definitely exist.

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throwawayaway
Rhetorical, hard to prove definitely. I wonder will we see more posthumous
exhonorations of people that got the death penalty out of this.

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contingencies
Just last month there was an exhibition in Paris at the excellent Jeau de
Paume gallery featuring a video exploring this phenomenon in the US by artist
Taryn Simon, who actually tracked down numerous people who had been falsely
imprisoned for her 2003 project _The Innocents_. More info at
[https://en.wikipedia.org/wiki/Taryn_Simon](https://en.wikipedia.org/wiki/Taryn_Simon)
and
[https://books.google.com/books?id=RRoiDl9rJtoC&printsec=fron...](https://books.google.com/books?id=RRoiDl9rJtoC&printsec=frontcover&dq=isbn:9781884167188&hl=en&sa=X&ei=qhZqVe_gD4_GogT12IDgBQ&ved=0CB4Q6AEwAA#v=onepage&q&f=false)

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throwawayaway
Interesting! I suppose there's a perverse incentive for the system not to
track the falsely imprisoned down. They have a right to sue for false
imprisonment.

