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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

#161

Post by throwaway2245 »

badRNG wrote: post #40
pc86 wrote: post #31

Earlier quoted context omitted.

You say that as if these were mistakes or unfortunate culminations of circumstance. The man committed fraud and sent innocent, grieving parents to prison by proxy. I don't think it's unreasonable to expect that to be 0.00% and punish those harshly who exceed that metric.

If I'm a juror, and the evidence presented happens to have a false positive rate of 1%, that certainly meets my understanding of "a reasonable doubt."

Is it bad that I'd guess you would be excluded from a jury if you admitted this upfront?

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

#162

Post by Eric_WVGG »

buttercraft wrote: post #106
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?

Paying investigators per conviction is a sure way to create incentive.

Exactly. "Product X caught 25% more bad guys than Product Y" this stuff just writes itself.

Policing is driven by numbers. There was a whole season of The Wire about this.

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

#163

Post by jlgaddis »

Zenst wrote: post #34
marcodiego wrote: post #23

Wouldn't this set a precedent to eventually force any forensic software to become open source?

Not per-say, though it certainly affords it the same level of scrutiny. Which may well be a win as open source already has that. However, even open source has bugs that pass scrutiny as many CVE's can attest, so whilst a code review may find nothing wrong, that in itself could be used by a lawyer to create reasonable doubt, if the lawyer is good.

> per-say

https://en.wiktionary.org/wiki/per_se

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

#164

Post by bardworx »

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?

Ok, maybe I’m naive, but why is that obvious?

Not arguing just trying to understand.

My rationale is: prosecutors have to weigh an “easy” conviction vs the possibility that labs that always guarantee results may be biased. In the event that they get caught up with a biased lab, wouldn’t it look bad for their reputation? As in, they can’t even perform due diligence on their sources, how can you trust them in a promoted role?

Or am I just naive on how the legal system works?

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

#165

Post by Scandiravian »

watwut wrote: post #125
Scandiravian wrote: post #84

Earlier quoted context omitted.

I completely agree, but if the reviewer isn't able to (with some amount of accuracy) predict the impact the committed code will have on overall behaviour, then there's very limited value on doing the review in the first place

In any larger project, the reviewer are not able to predict impact from reading commit. More importantly, typical reviewer have only small partia area where he has good idea about which commit is bad idea. He however does not understand whole codebase. Knowing what the whole does and knowing what my module does are two different things.

I again completely agree with you

Looking back at my reply, I think I should have added a bit of background to clarify my comment

My master's degree is in bioinformatics and I worked in the biotech industry until about a year ago. I mainly worked as a consultant for top 20 pharma companies, but also did work on different in-house projects and in academia

From my experience in the industry, I find it very unlikely that the software mentioned in the article is structured in a modular way. I've yet to see good software practices outside one or two academic projects. Most pharma companies still use copying and renaming folders as version control. Naturally I'm sceptical of any code coming from the biotech industry

On top of that, it's written in MATLAB. I have only ever seen this used by statisticians and university researchers, never by software engineers

I'm therefore willing to bet, that when the reviewers open the source code, they'll find unstructured mess of spaghetti code, that has never been refactored, reviewed or tested

So yes - I agree in all your points, but I find it unlikely that they're being applied to this particular project

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

#166

Post by AS37 »

R0b0t1 wrote: post #148
AnIdiotOnTheNet wrote: post #87

Earlier quoted context omitted.

> Holy shit that is bad. Even as a lay person I know that there are gaps between skull plates. Sure, but can you tell them apart from a fracture caused by injury? Presumably someone knowledgeable in medicine should be able to, but maybe it is one of those things that isn't as obvious as we, the uneducated outsider, might think.

That's an extremely flawed argument. If you can't explain it to a layman then you don't understand it. If you can't tell whether it's a gap or a fracture -- you can't get a conviction. "It just looks like it" is not a valid reason.

Interestingly there's an area of psychology called Naturalistic Decision Making which studies how experts make decisions that they can't explain. (Example: a firefighter may be able to pinpoint where a fire is before they enter a house and see it.)

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

#168

Post by jlgaddis »

unnouinceput wrote: post #45
jonnycomputer wrote: post #13

Earlier quoted context omitted.

Who is "they"

Probably "they" refer to prosecution. And yeah, why is prosecution going with that lab/software only? One reason is probably the DNA available for more testing is not enough / one testing could been done reliable with DNA taken from crime scene. Other reason might be behind the scenes incentives, which seems is the defense strategy here

> why is prosecution going with that lab/software only?

Presumably becquse that lab/software gave them the answer they were looking for.

Why pay for even more lab/software testing when you've already got what you want (especially when it's a possibility that the additional testing will contradict the first)?

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

#169

Post by _jal »

tantalor wrote: post #29
MaxBarraclough wrote: post #16

Earlier quoted context omitted.

> Forensic labs and companies are expert witnesses with black box processes and the incentive to protect the authority of their profession. I imagine they're also incentivised to favour a result indicating guilt.

Why? The risk to their reputation & livelihood for a false positive should temper that.

Livelihood is frequently the reason why biases creep in. Independent labs tend to do better.

Here's a look at two different Texas crime labs. Compare and contrast, and see if you can spot the differences.

https://gritsforbreakfast.blogspot.com/2021/02/beyond-aid-to...

It starts with one pledging to:

   aid law enforcement in the detection, suppression, and prosecution of crime
whereas the other seeks to

    provide medical examiner and crime laboratory services of the highest quality in an unbiased manner with uncompromised integrity.
and goes from there.

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

#170

Post by Scandiravian »

aaron695 wrote: post #101

This isn't a DNA testing kit as one would normally think - "TrueAllele uses a hierarchical Bayesian probability model that adds genotype alleles, accounts for artifacts, and determines variance to explain STR data and derive parameter values and their uncertainty. The computer employs Markov chain Monte Carlo (MCMC) statistical sampling to solve the Bayesian equations. The resulting joint posterior probability provid…

How is that different from a DNA testing kit "as one would normally think"?
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