When cardiologists at a Dublin teaching hospital set out to test whether a surname could shape someone's health, their whole case came down to eight patients named Brady. All eight had received pacemakers, devices often used to treat bradycardia, a slower-than-normal heartbeat. That was enough for the team to report that Bradys were more than twice as likely as other Dubliners to need one.
The paper, published in The BMJ's 2013 Christmas issue, carried the tongue-in-cheek title "The Brady Bunch?" It was written with a wink, but it doubles as a sharp lesson in how a statistically significant result can grow out of very small numbers.
