In biometric systems preventing false positive is usually far more important than preventing false negatives. In what situations can false negatives be more serious than false positives?

  • 1
    Your assumption is not accurate. It is always a tradeoff, it is the cross-over rate that is really important. Otherwise, it would be simple to tune a biometric authentication mechanism to never have any false positive (obviously, by keeping almost everybody out).
    – AviD
    Commented Oct 27, 2012 at 20:51
  • Smart guns immediately come to mind.
    – user42178
    Commented Dec 12, 2014 at 2:23

1 Answer 1


A false negative is when biometric systems fail to recognize an authentic individual, which would lead to something not happening. Depending on what that something is there could be various consequences:

  • Personal: An owner of a safe may be prevented from accessing that safe, leading to him/her being unable to access a necessary resource. Say they really need the money that's in there
  • Institutional: Say my entire server infrastructure is down, I need to access my data center to restore service. Ever minute is losing my company thousands of dollars in revenue. The biometric system doesn't recognize me, therefore the company loses more money and reputation
  • Safety: A staff member in the datacenter collapses on the floor in cardiac arrest, the biometric system doesn't recognize me when I try to go to her CPR. She could die before I get to her
  • Thanks, Can you also mention a normal situation that false negative shoulb be avoided more seerius than false negative?
    – Webber
    Commented Oct 28, 2012 at 5:08
  • @Webber, I think what you're asking is a normal situation where a false negative would be worse than a false positive. Nothing comes to mind.
    – GdD
    Commented Oct 28, 2012 at 7:40
  • 1
    @GdD - something that comes to mind is when the security gained overwhelms usability to the point of users opting for a different security - for example a smartphone with not-extremely-sensitive information, where the choices are between a fingerprint scanner with a rare false positive is better than the user being annoyed with too many false negatives and not using the security feature at all (or perhaps using only a secondary(well.. primary) security like a pin or password). Commented Dec 12, 2014 at 3:45

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