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Accused murderer wins right to check source code of DNA testing kit

theregister.com

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Re: Accused murderer wins right to check source code of DNA testing kit

#151

Post by yholio »

JoeAltmaier wrote: post #52
motohagiography wrote: post #10

It's an important development. Forensic labs and companies are expert witnesses with black box processes and the incentive to protect the authority of their profession. They are as likely to lie as any other witness. Perhaps even moreso. "Those arguing on behalf of the defense cited past problems with other genetic testing software such as STRmix and FST (Forensic Statistical Tool). Defense expert witnesses Mats Heim…

I'm not so sure we should be allowing challenges to expert witness, with no evidence. That sounds like a rich source of abuse of the system, like a big company filing thousands of briefs to delay a case. It's important for experts to use validated, tested equipment. That's clear. And by the sound of it that is happening (stories of how code was tested and found wanting confirm that; stories of double-blind testing).…

> I'm not so sure we should be allowing challenges to expert witness, with no evidence

Any challenge is "allowed" in the sense that the parties can try to convince the judge there is a flaw.

The question is one of burden of proof: should the expert prove they have a trustworthy result, or should the expert testimony stand on their credibility alone, and the defense scramble to poke holes into it armed with incomplete information.

For a system that can put people into jail for life and that acts as a direct extension of state power, it's obvious the latter can have disastrous consequences. Effectively, any one who acquirers the "judicial expert" title can put people in jail at their whim.

Re: Accused murderer wins right to check source code of DNA testing kit

#152

Post by jdironman »

lwigo wrote: post #128
throw2838 wrote: post #98

Earlier quoted context omitted.

Draeger requires calibration prior each use for temperature and humidity. It is easy to get it thrown out as evidence.

When the officer shows up and swears under oath that he "calibrated it that morning" it's not so easy. :shrug:

Temps vary throughout the day.

Re: Accused murderer wins right to check source code of DNA testing kit

#153

Post by AS37 »

[deleted] wrote: post #127

[deleted]

I'd like to encourage you, 5 minutes after you learn about someone's existence, not to wish for their death, execution, imprisonment, and /or disenfranchisement. The real world is too complicated to judge correctly in that time.

As well, please remember that the comment guidelines exist at https://news.ycombinator.com/newsguidelines.html

Re: Accused murderer wins right to check source code of DNA testing kit

#154

Post by glitchc »

calciphus wrote: post #50
TheRealDunkirk wrote: post #41

Earlier quoted context omitted.

Yes, just like voting machines. But how do we confirm that the software which was vetted is the software that was actually _used_?

Compile it, run it with the same inputs the prosecution claims was provided, and see if you get the same result. That's sorta the point of computers, right? Same inputs on the same program, same output?

Same compiler? Same configuration? Same OS? There will be variations in the output. How much variation is reasonable?

Re: Accused murderer wins right to check source code of DNA testing kit

#155

Post by fsflover »

glitchc wrote: post #154
calciphus wrote: post #50

Earlier quoted context omitted.

Compile it, run it with the same inputs the prosecution claims was provided, and see if you get the same result. That's sorta the point of computers, right? Same inputs on the same program, same output?

Same compiler? Same configuration? Same OS? There will be variations in the output. How much variation is reasonable?

https://reproducible-builds.org/

Re: Accused murderer wins right to check source code of DNA testing kit

#157

Post by x0x0 »

josephorjoe wrote: post #108
JoeAltmaier wrote: post #52

Earlier quoted context omitted.

I'm not so sure we should be allowing challenges to expert witness, with no evidence. That sounds like a rich source of abuse of the system, like a big company filing thousands of briefs to delay a case. It's important for experts to use validated, tested equipment. That's clear. And by the sound of it that is happening (stories of how code was tested and found wanting confirm that; stories of double-blind testing).…

defendants should always be able to challenge expert witnesses qualifications. and how could anyone on hacker news claim there is 'no evidence' that unreviewed software may do something other than what people claim it does? especially if it 170,000 lines of matlab? from the article: > "Without scrutinizing its software's source code – a human-made set of instructions that may contain bugs, glitches, and defects – in…

Particularly when TrueAllele specializes in

>probabilistic genotyping [1]

and

>solves mixed DNA samples, low template DNA and kinship problems [1]

And the product sheet discusses

> models for PCR artifacts [2]

This sure feels like they go way beyond typical dna match technology into maximally extracting information via statistics, so their methods definitely should be open for review.

[1] https://www.cybgen.com/products/casework.shtml

[2] https://www.cybgen.com/solutions/brochures/unique_features.p...

Re: Accused murderer wins right to check source code of DNA testing kit

#158

Post by nickodell »

breck wrote: post #131
phire wrote: post #93

> The co-founder of the company, Mark Perlin, is said to have argued against source code analysis by claiming that the program, consisting of 170,000 lines of MATLAB code, is so dense it would take eight and a half years to review at a rate of ten lines an hour. First, the defence doesn't necessarily have to evaluate all 170,000 lines. They just need to find one buggy line which could potentially overturn the result.…

Lol. If it would take 8.5 yrs to review, it's probably god awful, and should never ever ever be used to convict someone of such a crime. My prediction: this firm will probably try to get removed from the case, rather than open source their shitty code. Source: I've worked on MATLAB codebases for various genomics research projects in the past.

>My prediction: this firm will probably try to get removed from the case, rather than open source their shitty code.

That isn't necessarily their choice. The prosecutors will make the decision about whether to withdraw the DNA evidence. They probably won't, given that they would need to give the defendant a new trial, which could lead to an accused murderer getting off. A bad look for any prosecutor.

More to the point, if the firm withdraws from any case where their credibility is questioned, what does that say to law enforcement agencies who are thinking about using their software?

Re: Accused murderer wins right to check source code of DNA testing kit

#159

Post by themaninthedark »

curryst wrote: post #116
calciphus wrote: post #50

Earlier quoted context omitted.

Compile it, run it with the same inputs the prosecution claims was provided, and see if you get the same result. That's sorta the point of computers, right? Same inputs on the same program, same output?

> Compile it, run it with the same inputs the prosecution claims was provided, and see if you get the same result. That's sorta the point of computers, right? Same inputs on the same program, same output? One difficulty here is that the input is a real world effect. That means the answers are rarely exactly the same. The last time I looked, breathalyzers have a ~50% margin of error. So if you blow a 0.06, your BAC is…

> The whole thing, from top to bottom, is just a long chain of poorly aligned incentives. Field sobriety tests are even worse. The fact that your license can be revoked for refusing the test under the above grounds is nothing short of an end-run around the 4th amendment by declaring driving a "privilege, not a right"

I agree and I wish I had a better solution.

>They need to force people to go in for a blood draw to establish BAC.

I know the intention is good, but that seems like a very scary proposition to me. I think the same poorly aligned incentives will line up here too.

"We are now partnered exclusively with X-clinic to do all the blood tests."

X-clinic just happens to tweak their procedure so that borderline samples end up showing under influence.

Re: Accused murderer wins right to check source code of DNA testing kit

#160

Post by drdrey »

Ma8ee wrote: post #149
kortilla wrote: post #81

Earlier quoted context omitted.

No, the question is what is the incentive for lying and claiming guilty? Do prosecutors choose different labs?

Of course prosecutors will favour expert witnesses that will help them get convictions. Why isn’t that obvious?

There are countries where the job of the prosecutor is to uncover the truth, not to convict someone at all costs:

https://en.wikipedia.org/wiki/Inquisitorial_system

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