How Biased People Are

DALY = disability-adjusted life years. It means how many years of life your intervention is giving people, but if they’re disabled then a year only gets partial credit. (E.g. if you keep them alive instead of dead for a year, but they can’t walk, then that’s only worth half a year of life. I don’t know the actual numbers they use for any disabilities.)

This charity site claims these interventions should be estimated as about equally good. They are giving a 1000x effectiveness discount rate to thought experiments vs. something that worked in 15 RCTs (randomized, controlled trials).

The basic reason for the large discount, which they talk about in the article, is that people are extremely biased in the positive direction (higher effectiveness) when estimating how well charity interventions work. When they get more accurate information/evidence, then cost effectiveness reliably goes down, often by a large amount. (If people were unbiased, then when they get more accurate information, their estimates should be adjusted up around half the time and down around half the time. That’s what you’d expect if their errors were random.)