5 ms·

On the one hand, I'm really strongly in favor of this, but there's one thing that makes me question the 100% test coverage paradigm: what happens when a kit is

On the one hand, I'm really strongly in favor of this, but there's one thing that makes me question the 100% test coverage paradigm: what happens when a kit is collected, but police use other methods (victim testimony, security footage, eyewitness accounts, etc.) to apprehend the perpetrator? That doesn't seem like an instance where a kit necessarily must be tested.

DanBC 11y ago
Or when both people accept that sex happened, but one says it was consensual while the other says it wasn't.
mikeash 11y ago
In a case like that, why not test the kit anyway just to be sure? If it matches the suspect, then you can rest even easier knowing you got the right person. If it doesn't, then you've avoided imprisoning an innocent. The cost of the test is about the same as a few days of imprisoning the accused, who will probably be put away for many years, so there's no sense trying to trim costs there.
- facepalm 11y ago
  Because it costs 1500$ perhaps?
  - vijayr 11y ago
    It is better to spend that 1500 and make sure to send the right person to jail (even if it is redundant) than take a chance with eyewitness testimony. 1,500$ is nothing compared to the life and freedom of someone.
    - facepalm 11y ago
      What if the rapist already confessed? 1500$ would buy a police officer a nice computer. In many countries the police lags far behind the criminals in technical equipment. Edit: hit HN's comment limit again. Anyway: consider this - what if the test isn't 100% reliable? What makes you think it is - because you want to believe that 100% truth can be established? What if it has a false negative rate of 30%, so 30% of actual rapists (who might already have confessed) would be cleared by the test?
      - dragonwriter 11y ago
        > What if the rapist already confessed? Revealing innocents pressured into plea deals would have social value. Were you under the impression that innocent people never confess?
      - vijayr 11y ago
        IMHO, an individual's life and freedom is worth way more than any dollar amount, but that is just my opinion. That said: DNA tests are far more reliable than eyewitness accounts. Innocent people confess to crimes all the time.
  - mikeash 11y ago
    I did explicitly mention cost savings in my comment.... You'll easily be spending 100x that much on the trial and imprisonment. Spending an extra 1% to get some hard physical evidence seems like cheap insurance.
    - facepalm 11y ago
      Doesn't it depend on the circumstances? Sometimes the kit might not reveal any useful information. You assume because it is some sciency sounding thing it will give you 100% information, but what do you actually know about those kits? They might also just yield some likelihood or even false pointers. Why do you automatically assume the police chose to ignore important evidence? The article doesn't tell us anything about that.
      - mikeash 11y ago
        If they're not useful then don't collect them. There's no circumstance where it makes sense to collect them but not test them. I don't think this dichotomy rests on any assumptions about how they work or what information they give. I'm sure there are some circumstances where testing the kit is completely redundant. But how often does that happen? If it's rare, why bother carving out an exception?
        facepalm 11y ago
        What makes you think it is rare? Maybe most of the time the rapists confess without the need to use the kit (maybe the existence of the kit is enough to make them confess, so no need to actually process it). And maybe collecting the information from the kits is just standard procedure, like photographing crime scenes, taking finger prints, and so on (all the stuff we see on TV).
        mikeash 11y ago
        I'd be shocked if most rapists confessed. That would, as far as I know, make rape completely unique in the world of crime. Additionally, as another commenter mentioned, false confessions exist. I don't understand your "standard procedure" comment. Either collecting the kits is useful or it is not. If it is, then test them. If it is not, don't collect them. If collecting them is "standard procedure" then change the procedure.
  - Vraxx 11y ago
    Seriously.. To agree with a sibling poster, $1500 is a paltry fee to pay to be sure that you imprison the right person. Especially since it isn't a trivial charge either. $1500 is also dwarfed by the amount it will cost to imprison the suspect for the duration of their sentence should they be convicted.
    - facepalm 11y ago
      Maybe the kits don't really "make you sure". What do you know about them?
LordKano 11y ago
100% is a reasonable goal. Victims and Eyewitnesses can and do make mistakes. Security footage can show someone who looks like a suspect but DNA (when properly tested) provides irrefutable proof. In many cases, especially old cases for which there have already been convictions, prosecutors are highly resistant to the idea of testing the DNA because they can lead to overturned convictions.
- dragonwriter 11y ago
  > Victims and Eyewitnesses can and do make mistakes. Security footage can show someone who looks like a suspect but DNA (when properly tested) provides irrefutable proof. DNA (when properly tested) can provide a substantial degree of certainty of whether the person from whom the material in one sample came was the same as the person from whom the material in another sample came (and can provide an even greater certainty that that is not the case.) Of course, the provenance of at least one of the samples in a normal criminal investigation is itself to subject to all kinds of uncertainties which are resolved to what amounts to testimony of witnesses (in documentary form) to various steps in the process. So, in the sense that witnesses are fallible or potentially malicious, it doesn't actually eliminate that problem.
leejoramo 11y ago
Rapists often repeat the crime on new victims. Even in such a situation as you suggest where the kit is not needed to prosecute a given crime, the data from the kit could be useful in unsolved cases for which a kit was processed but no suspect was identified.
rodgerd 11y ago
If you're testing all the kits, you may find you have information you didn't know you had - like the presence of a rapist in rapes they hadn't been suspected of.

DanBC 11y ago

Or when both people accept that sex happened, but one says it was consensual while the other says it wasn't.

mikeash 11y ago

In a case like that, why not test the kit anyway just to be sure? If it matches the suspect, then you can rest even easier knowing you got the right person. If it doesn't, then you've avoided imprisoning an innocent. The cost of the test is about the same as a few days of imprisoning the accused, who will probably be put away for many years, so there's no sense trying to trim costs there.

facepalm 11y ago
Because it costs 1500$ perhaps?
- vijayr 11y ago
  It is better to spend that 1500 and make sure to send the right person to jail (even if it is redundant) than take a chance with eyewitness testimony. 1,500$ is nothing compared to the life and freedom of someone.
  - facepalm 11y ago
    What if the rapist already confessed? 1500$ would buy a police officer a nice computer. In many countries the police lags far behind the criminals in technical equipment. Edit: hit HN's comment limit again. Anyway: consider this - what if the test isn't 100% reliable? What makes you think it is - because you want to believe that 100% truth can be established? What if it has a false negative rate of 30%, so 30% of actual rapists (who might already have confessed) would be cleared by the test?
    - dragonwriter 11y ago
      > What if the rapist already confessed? Revealing innocents pressured into plea deals would have social value. Were you under the impression that innocent people never confess?
    - vijayr 11y ago
      IMHO, an individual's life and freedom is worth way more than any dollar amount, but that is just my opinion. That said: DNA tests are far more reliable than eyewitness accounts. Innocent people confess to crimes all the time.
- mikeash 11y ago
  I did explicitly mention cost savings in my comment.... You'll easily be spending 100x that much on the trial and imprisonment. Spending an extra 1% to get some hard physical evidence seems like cheap insurance.
  - facepalm 11y ago
    Doesn't it depend on the circumstances? Sometimes the kit might not reveal any useful information. You assume because it is some sciency sounding thing it will give you 100% information, but what do you actually know about those kits? They might also just yield some likelihood or even false pointers. Why do you automatically assume the police chose to ignore important evidence? The article doesn't tell us anything about that.
    - mikeash 11y ago
      If they're not useful then don't collect them. There's no circumstance where it makes sense to collect them but not test them. I don't think this dichotomy rests on any assumptions about how they work or what information they give. I'm sure there are some circumstances where testing the kit is completely redundant. But how often does that happen? If it's rare, why bother carving out an exception?
      - facepalm 11y ago
        What makes you think it is rare? Maybe most of the time the rapists confess without the need to use the kit (maybe the existence of the kit is enough to make them confess, so no need to actually process it). And maybe collecting the information from the kits is just standard procedure, like photographing crime scenes, taking finger prints, and so on (all the stuff we see on TV).
        mikeash 11y ago
        I'd be shocked if most rapists confessed. That would, as far as I know, make rape completely unique in the world of crime. Additionally, as another commenter mentioned, false confessions exist. I don't understand your "standard procedure" comment. Either collecting the kits is useful or it is not. If it is, then test them. If it is not, don't collect them. If collecting them is "standard procedure" then change the procedure.
- Vraxx 11y ago
  Seriously.. To agree with a sibling poster, $1500 is a paltry fee to pay to be sure that you imprison the right person. Especially since it isn't a trivial charge either. $1500 is also dwarfed by the amount it will cost to imprison the suspect for the duration of their sentence should they be convicted.
  - facepalm 11y ago
    Maybe the kits don't really "make you sure". What do you know about them?

LordKano 11y ago

100% is a reasonable goal. Victims and Eyewitnesses can and do make mistakes. Security footage can show someone who looks like a suspect but DNA (when properly tested) provides irrefutable proof. In many cases, especially old cases for which there have already been convictions, prosecutors are highly resistant to the idea of testing the DNA because they can lead to overturned convictions.

dragonwriter 11y ago
> Victims and Eyewitnesses can and do make mistakes. Security footage can show someone who looks like a suspect but DNA (when properly tested) provides irrefutable proof. DNA (when properly tested) can provide a substantial degree of certainty of whether the person from whom the material in one sample came was the same as the person from whom the material in another sample came (and can provide an even greater certainty that that is not the case.) Of course, the provenance of at least one of the samples in a normal criminal investigation is itself to subject to all kinds of uncertainties which are resolved to what amounts to testimony of witnesses (in documentary form) to various steps in the process. So, in the sense that witnesses are fallible or potentially malicious, it doesn't actually eliminate that problem.

leejoramo 11y ago

Rapists often repeat the crime on new victims. Even in such a situation as you suggest where the kit is not needed to prosecute a given crime, the data from the kit could be useful in unsolved cases for which a kit was processed but no suspect was identified.

rodgerd 11y ago

If you're testing all the kits, you may find you have information you didn't know you had - like the presence of a rapist in rapes they hadn't been suspected of.