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View Diary: Court blocks Florida drug testing for welfare applicants (58 comments)

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  •  If she has a phd in psychology (1+ / 0-)
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    leftangler

    One might hope that she knows some statistics. You could point out to her that when the percentage of users in the tested population is low the rate of false positives is very high. Unless drug use is pervasive a large percentage of those positive results are false, so relying on them to take drastic actions like removing children from a household will inevitably lead to a great deal of injustice.

    Take our present case. Of the 7000+ who took the test about 30 tested positive. That's less than 1/2 of 1%.  If the test is 99.5% accurate this means that fully half of the 30 who tested positive are likely to be falsely accused.

    Take away someones kids if a positive drug test is just as likely to be wrong as right?
    Explanation of the probability of a false positive.

    We are the principled ones, remember? We don't get to use the black hats' tricks even when it would benefit us. Political Compass: -6.88, -6.41

    by bmcphail on Mon Oct 24, 2011 at 09:40:40 PM PDT

    [ Parent ]

    •  This seems counter intuitive, but..... (1+ / 0-)
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      PsychoSavannah

      Look at the lower limit of the scale:

      if drug use among those 7000 was hypothetically zero, a 99.5% accurate test would falsely accuse 35 people, with a 100% error rate.

      Baz

      We are the principled ones, remember? We don't get to use the black hats' tricks even when it would benefit us. Political Compass: -6.88, -6.41

      by bmcphail on Mon Oct 24, 2011 at 09:50:07 PM PDT

      [ Parent ]

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