Lies, Damned Lies, And Statistics

Did you see the news headline yesterday that, according to a recent study by the American Chemical Society, nine out of ten pieces of paper currency they sampled around the United States contained traces of cocaine? That's 90%, a pretty shocking figure. "Is everyone in the country doing drugs!?!" was the intended hysterical inference, obviously.

But that shock lasts only until you read beneath the screaming headline and learn that these were mostly minute traces being detected, and that even bills not involved in drug deals can become minutely contaminated during the automated bill-counting process in banks. So this was really a story about testing technology and about how frequently our currency circulates through the banking system.