Open thread, February 15-28, 2013

David_Gerard

If it's worth saying, but not worth its own post, even in Discussion, it goes here.

Would this gross example of irrationality be tolerated in other professions?

What gross example of irrationality? The vast majority of people with headaches don't have anything to worry about.

The question is whether "people with headaches" is the right reference class. If the headache is unusually severe or persistent, it makes sense to look deeper. Also, a doctor can ask for details about the headache before prescribing the expensive tests.

-1A1987dM13y

“The vast majority” != “All”. What's wrong with “you most likely have nothing to worry about, but I suggest doing this exam the off-chance that you do”? You've got to multiply the probability by the disutility, and the result can be large enough to worry about even if the probability is small. (Yes, down that way Pascal's mugging lies, but still.) EDIT: Okay, given the replies to this comment I'm going to Aumann my estimate of the cost of tests for rare diseases upwards by a couple of orders of magnitude. Retracted.