Updated Sep. 12, 2013
I HAVE before me the abstract of a 1993 study published in the British Medical Journal provocatively titled "Is Friday the 13th Bad for Your Health?"
With the aim of mapping "the relation between health, behaviour, and superstition surrounding Friday 13th in the United Kingdom," its authors compared the ratio of traffic volume to the number of automobile accidents on two different days, Friday the 6th and Friday the 13th, over a period of years.
Amazingly, they found that in the region sampled, while consistently fewer people chose to drive their cars on Friday the 13th, the number of hospital admissions due to vehicular accidents was significantly higher than on "normal" Fridays. Their conclusion:
"Friday 13th is unlucky for some. The risk of hospital admission as a result of a transport accident may be increased by as much as 52 percent. Staying at home is recommended."
Paraskevidekatriaphobics — people afflicted with a morbid, irrational fear of Friday the 13th — will be pricking up their ears about now, buoyed by seeming evidence that the source of their unholy terror might not be so irrational after all. It's unwise to take solace in a single scientific study, however, especially one so peculiar. I suspect these statistics have more to teach us about human psychology than the ill-fatedness of any particular date on the calendar.
Friday the 13th, 'the most widespread superstition'
The sixth day of the week and the number 13 both have foreboding reputations said to date from ancient times. It seems their inevitable conjunction from one to three times a year (there will be two such occurrences in 2013, exactly 13 weeks apart) portends more misfortune than some credulous minds can bear. According to some sources it's the most widespread superstition in the United States today. Some people refuse to go to work on Friday the 13th; some won't eat in restaurants; many wouldn't think of setting a wedding on the date.
How many Americans at the beginning of the 21st century suffer from this condition? According to Dr. Donald Dossey, a psychotherapist specializing in the treatment of phobias (and coiner of the term paraskevidekatriaphobia, also spelled paraskavedekatriaphobia), the figure may be as high as 21 million. If he's right, no fewer than eight percent of Americans remain in the grips of a very old superstition.
Exactly how old is difficult to say, because determining the origins of superstitions is an inexact science, at best. In fact, it's mostly guesswork.