

New York Passes DNA Requirement For Convicted Criminals - nostromo
http://www.npr.org/2012/03/15/148692189/n-y-passes-dna-requirement-for-convicted-criminals

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droithomme
Doing blind searches of samples on large DNA databases in order to find cold
hits gives you a very high probability of a false match. A match that the
falsely accused defendant will be quite difficult to challenge since there is
a general belief by the public that DNA matches on a few markers are
irrefutable proof of identity.

DNA can more strongly connect a suspect who is already known through other
information. Doing blind searches isn't science and it isn't justice. Those
advocating this are dangerous, not to be trusted, and possibly ignorant of
statistics.

Please see:
[http://www.bioforensics.com/articles/Legally%20Scientific%20...](http://www.bioforensics.com/articles/Legally%20Scientific%20\(Cold%20Hits%20vs%20Hard%20Facts\).html)

> For instance, if a DNA test capable of distinguishing between 'unrelated'
> people with one million to one confidence was used to create a database of
> two million personal profiles from a population of 20 million potential
> suspects you could be pretty certain that most crime stain profiles run
> against it would produce at least one cold hit.

> You could also be more than 90% certain that it would be the wrong cold hit.
> You could further expect that around 80% of the personal profiles on the
> database would match at least one other on record from a different person.

> Problems like these had led the 1996 National Research Council publication
> "The Evaluation of Forensic Evidence" (NRC-II) to recommend that "When the
> suspect is found by a search of a DNA database, the random match probability
> should be multiplied by N, the number of persons in the database".

