One of the most widespread superstitions in modern society is the idea that Friday the 13th is unlucky -- a phobia that may stretch all the way back to 1780 B.C and the Code of Hammurabi.
We're here to dispel it.
There have actually been a number of studies looking at whether enough unfortunate events occur on Friday the 13th to justify "friggatriskaidekaphobia." None of them have turned up any good evidence that they do. Here's a quick look at the data.
The evidence that Friday the 13th isn't unlucky
One of the first studies of Friday the 13th looked at traffic accident rates in a London suburb, and found that significantly more hospital admissions due to accidents did occur.
But that doesn't necessarily mean Friday the 13th is unlucky. Others subsequently pointed out that the sample size (one town and 65 total accident-related injuries) was pretty small. Given that Friday the 13th is just an artifact of our Gregorian calendar and there's no known mechanism through which it could cause bad luck, the data wasn't strong enough to support such a claim.
A more plausible hypothesis might be that Friday the 13th itself doesn't cause bad luck, but it does lead people to behave differently out of fear or anxiety, thereby causing things like accidents.
Subsequent studies, though, don't support this idea idea either.
While a Finnish study found female drivers were more likely to get in accidents on the Friday the 13th, a follow-up found the correlation disappeared with better data and more controls. A German study similarly found that the number of accidents and errors that occur during hospital operations is pretty much the same on Friday the 13th as on other days.
A few other studies have looked at the very plausible idea that stock markets might perform more poorly on Friday the 13th — because of investors' superstition — but surprisingly, they found the markets actually do slightly better, on average, than on other days.
The superstition might be widespread and deeply rooted, but there's no real reason to believe Friday the 13th is unluckier than any other day.