I was alerted to the great news that a pair of conjoined twins have been successfully surgically separated. Reported in The Daily Mail, it is stated that only one in ten million survive this operation. A comment on facebook questioned whether ten million such operations had been performed or was the figure just “plucked out of the air” (. . . I’ve told you a million times not to exaggerate). Checking on the source of the statistic, the Facing the World website uses it slightly differently:
Cases of craniopagus (head-to-head) conjoined twins are extremely rare – only 1:10 million survive to infancy.
This is not the same as the Daily Mail’s claim. The practice of slightly altering statistics to fit the story or sometimes blatant misreporting often happens because journalists are on a deadline and often do not understand the things they report, or just want to tweak the facts and figures to make a better story. So the moral of this story is to check the sources of tabloid stories, or any news story for that matter.
If you need an easy-to-read crash course in statistics then I recommend: Darrell Huff’s entertaining book: How to Lie with Statistics.