Believe it or not, a handful of studies have actually investigated this issue. After all, superstitious beliefs can affect behavior, and behavior definitely affects health.

But let me quickly reassure those of you who might be slightly paraskevidekatriaphobic (irrationally fearful of Friday the 13th): Although few and small, the studies on this topic strongly suggest that you’re not at increased risk of having an accident  today — well, unless your fear and anxiety about today gets the better of you.

A gender dispute
I’ll start with the completely good-news study: In 2008, statisticians working for a Dutch insurance company reported that people in the Netherlands experienced fewer accidents (and fires and thefts) on Fridays that fell on the 13th of the month than on Fridays that fell on other dates  (7,500 versus 7,800 reports, on average).

On the other hand, a 2002 Finnish study came up with a more worrisome finding. It reported that on Friday the 13th, the risk of dying in a traffic accident for women (not men) increased by 63 percent. The study’s author suggested that the increased risk might be caused by women’s “twice-as-high prevalence of neurotic disorders and anxiety symptoms,” which makes them “more susceptible to superstition and worsening of driving performance.”

Needless to say, that finding didn’t go down well, particularly when all sorts of methodological problems were found with the study. A couple of years later, two other Finnish researchers reported that their investigation revealed no increase in traffic accidents — among women or men — on Friday the 13th.

“However,” they concluded, a bit ominously, “this does not imply a non-existent effect of superstition related anxiety on accident risk as no exposure-to-risk data are available. People who are anxious of ‘Black Friday’ may stay home, or at least avoid driving a car.”

Will the boss agree?
By far, though, my favorite study on this topic (for its readability alone) remains a 1993 one published in the British Medical Journal. It made the slightly startling finding that although fewer British people drove on Friday the 13th, compared with other Fridays, driving-related accidents increased by as much as 52 percent on that day.

The authors’ must-be-tongue-in-cheek conclusion: “Staying at home is recommended.”

Here’s what they say:

Now, how to convince the boss?