"We spent ages... working... for child heart surgery... such a delicate area, trying to find the wording for... random error or binomial variability... [Y]ou can give a percentage... 95% . Well, am I going to be one of the 5% or one of the 95%? We don't know. It's just chance or luck, fortune. We can't... use those words in... delicate situations... operating on children... Then we came up with a good phrase... which we used and tested on parents... It's "unforeseeable factors," not "unforeseen factors," because that would suggest someone's to blame... [T]he unforeseeable factors could lead some people to... not survive the operation, and some to survive. So... we can put you in a group, but we can't go beyond that... [O]nly what develops over time, in terms of complications, or something like that, could... put... you in one group or another. "Unforeseeable factors," I really like that phrase. I try to use it all the time, I recommend it."