5 ms·

If DNA tests are so unreliable, how come they are still accepted in court?

kevin_thibedeau 8y ago
Because the public is ignorant of the problems with it and the judiciary likes tools that can win easy convictions. Breathalyzers don't actually measure blood alcohol and there is no credible way they can estimate it to three significant digits but courts allow them too. Polygraphs are pure bullshit but the examiner's word that someone is "lying" is taken as sacrosanct evidence in court.
- eanzenberg 8y ago
  Conspiracy theorist.
  - yetanother1980 8y ago
    Not sure about DNA testing. The other two examples are true. Across the Atlantic polygraphs are regarded as a comedy technology and breathalyser tests are sufficient grounds only for arrest and an actual blood test.
    - pfranz 8y ago
      I'm pretty sure most all jurisdictions allow you to request a blood test in lieu of a breathalyser. I assumed it was common knowledge polygraphs were junk, but at least Wikipedia says they're in common use in the U.S. but are considered controversial. I knew polygraphs were banned as a prerequisite for jobs in many areas and that many government jobs had them as part of the interview, but figured it was more of a stress test or hazing. I do think the bar for expert testimony and scientific evidence could use a lot of improvement in the U.S.
      - gnode 8y ago
        In the UK there used to be such a right to refuse the breath test and take a blood test instead. However it was removed. https://www.theguardian.com/society/2009/mar/15/drink-driving-blood-test-breathalyser https://www.theguardian.com/society/2009/mar/15/drink-drivin...
        yetanother1980 8y ago
        What the actual fuck? I didn't realise that the UK was so stupid. Is due process dead here?
      - deleted 8y ago
        [deleted]
    - thousandautumns 8y ago
      Polygraphs aren't admissible on this side of the Atlantic as evidence.
- nasredin 8y ago
  Polygraphs are not admissable IIRC. IIRC The Wire had an accurate description of its use as an interogation tool (note I did not say investigative tool).
stevenwoo 8y ago
I don't know if this is the commenter's intent but isn't there a potential false positive issue with DNA testing? Something along the lines of if only 0.01 percent of the world's population can match a DNA sequence found that still leaves us with a million matches where I just made up both those numbers.

Because the public is ignorant of the problems with it and the judiciary likes tools that can win easy convictions. Breathalyzers don't actually measure blood alcohol and there is no credible way they can estimate it to three significant digits but courts allow them too. Polygraphs are pure bullshit but the examiner's word that someone is "lying" is taken as sacrosanct evidence in court.

eanzenberg 8y ago
Conspiracy theorist.
- yetanother1980 8y ago
  Not sure about DNA testing. The other two examples are true. Across the Atlantic polygraphs are regarded as a comedy technology and breathalyser tests are sufficient grounds only for arrest and an actual blood test.
  - pfranz 8y ago
    I'm pretty sure most all jurisdictions allow you to request a blood test in lieu of a breathalyser. I assumed it was common knowledge polygraphs were junk, but at least Wikipedia says they're in common use in the U.S. but are considered controversial. I knew polygraphs were banned as a prerequisite for jobs in many areas and that many government jobs had them as part of the interview, but figured it was more of a stress test or hazing. I do think the bar for expert testimony and scientific evidence could use a lot of improvement in the U.S.
    - gnode 8y ago
      In the UK there used to be such a right to refuse the breath test and take a blood test instead. However it was removed. https://www.theguardian.com/society/2009/mar/15/drink-driving-blood-test-breathalyser https://www.theguardian.com/society/2009/mar/15/drink-drivin...
      - yetanother1980 8y ago
        What the actual fuck? I didn't realise that the UK was so stupid. Is due process dead here?
    - deleted 8y ago
      [deleted]
  - thousandautumns 8y ago
    Polygraphs aren't admissible on this side of the Atlantic as evidence.
nasredin 8y ago
Polygraphs are not admissable IIRC. IIRC The Wire had an accurate description of its use as an interogation tool (note I did not say investigative tool).

stevenwoo 8y ago

I don't know if this is the commenter's intent but isn't there a potential false positive issue with DNA testing? Something along the lines of if only 0.01 percent of the world's population can match a DNA sequence found that still leaves us with a million matches where I just made up both those numbers.