Originally Posted by engineer_sailor
In 89% of sailing fatalities from drowning the victim did not have a PFD
I generally do wear a PFD so I'm just playing devil's advocate here, but…
We have the data that 89% of drowning victims were not wearing a PFD and presumably 11% were. But to put that in context we need to know the overall level of PFD usage. For example, if only 11% of people routinely wear a PFD, then the fact that 11% of drowning victims were wearing a PFD would indicate that PFDs have no effect on survival rate.