An interesting thread started up on a /. article about how handwriting style “fingerprinting” is easily fooled. Since I made some of the posts, I’m mirroring it here:
There was a good article here (or possibly some other social news type site) about the inherent flaw in DNA databases and the weight given to DNA evidence.
The theory goes like this: the chances of getting a false positive on a part sample are something like 1/50million. You have 50 million people on the database. This means You’d expect a false positive on every search. If you’re unlucky enough to live close enough to a crime to have committed it, you could easily find yourself in court.
You’ll then have to defend yourself based on a 1 in 50 million probability to a jury who won’t understand the statistics. If you haven’t got a solid alibi, it would be a tough thing to do.
There’s probably a good Terry Pratchett quote about 1 in a million chances to be used here.