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We are quite familiar with the false positive paradox in diagnostic medical testing: in wide-scale testing of a low risk population, a substantial proportion of the positive test results may turn out to be false. In recent Chance News items have discussed [http://test.causeweb.org/wiki/chance/index.php/Chance_News_67#More_fuel_to_feed_the_fiery_controversy_over_mammograms mammograms] to screen for breast cancer, [http://test.causeweb.org/wiki/chance/index.php/Chance_News_85#PSA.2C_overdiagnosis.2C_and_anecdotal_evidence PSA test] for prostate cancer. | We are quite familiar with the false positive paradox in diagnostic medical testing: in wide-scale testing of a low risk population, a substantial proportion of the positive test results may turn out to be false. In recent Chance News items have discussed [http://test.causeweb.org/wiki/chance/index.php/Chance_News_67#More_fuel_to_feed_the_fiery_controversy_over_mammograms mammograms] to screen for breast cancer, [http://test.causeweb.org/wiki/chance/index.php/Chance_News_85#PSA.2C_overdiagnosis.2C_and_anecdotal_evidence PSA test] for prostate cancer. | ||
This Numbers Guy column addresses the risk of false positives in the NSA's Prism initiative that tracks electronic communications. Bialik cites [http://bayesianbiologist.com/2013/06/06/how-likely-is-the-nsa-prism-program-to-catch-a-terrorist/ analysis by Cory Chivers], a grad student at McGill University. | This Numbers Guy column addresses the risk of false positives in the NSA's Prism initiative that tracks electronic communications. Bialik cites [http://bayesianbiologist.com/2013/06/06/how-likely-is-the-nsa-prism-program-to-catch-a-terrorist/ analysis by Cory Chivers], a grad student at McGill University. Applying Bayes Theorem, Chivers find that there is only a 1-in-10,000 chance that an individual flagged by Prism will be an actual terrorist. | ||
Submitted by Bill Peterson, based on a suggestion from Margaret Cibes | Submitted by Bill Peterson, based on a suggestion from Margaret Cibes | ||
Revision as of 15:51, 19 August 2013
False positives at NSA
Do the numbers behind Prism add up?
by Carl Bialik, Numbers Guy blog, Wall Street Journal, 14 June 2013
We are quite familiar with the false positive paradox in diagnostic medical testing: in wide-scale testing of a low risk population, a substantial proportion of the positive test results may turn out to be false. In recent Chance News items have discussed mammograms to screen for breast cancer, PSA test for prostate cancer.
This Numbers Guy column addresses the risk of false positives in the NSA's Prism initiative that tracks electronic communications. Bialik cites analysis by Cory Chivers, a grad student at McGill University. Applying Bayes Theorem, Chivers find that there is only a 1-in-10,000 chance that an individual flagged by Prism will be an actual terrorist.
Submitted by Bill Peterson, based on a suggestion from Margaret Cibes