tough choices
my mother has to make a difficult choice. she needs surgery on her foot or she'll be crippled in 5 years. however, the operations and recovery will take a year. and they have only a 60% chance of success. if it works she'll be ambulatory for the rest of her life - about 11 years for a diabetic woman born in 1940. if it fails she'll be crippled forever immediately. there are several strategies she can follow. the simplest is minimizing the worst case, ie no surgery. or she can maximize the number of years she can walk. with surgery she expects to get 6 years (60% of (11-1) years). without surgery she expects 5 years. so she should have the operation. alternatively, she can look at it this way: she can trade 1 year of pain for 2 years of being crippled. yuck.