Yeah. The words “estimates” and “about” are right there in the quote. There is no pretension of certainty here, unless you think mere use of numbers amounts to pretended certainty.
But what is decision relevant is the expected value. So by best estimate do they mean expected value, or maximum likelihood estimate, or something else? To my ear, “best estimate” sounds like it means the estimate most likely to be right, and not the mean of the probability distribution. For instance, take the (B) option in “Why it can be OK to predictably lose”, where you have a 1% chance of saving 1000 people, and a 99% chance of saving no one, and the choice is non-repeatable. I would think the “best estimate” of the effectiveness of option (B) is that you will save 0 lives. But what matters for decision making is the expected value which is 10 lives.
Sorry if this is a stupid question, I’m not very familiar with GiveWell.
Fair question! I don’t know the answer. But I’d be surprised if the two came apart too sharply in this case (even though, as you rightly note, they can drastically diverge in principle). My sense is that GiveWell aims to recommend relatively “safe” bets, rather than a “hits-based” EV-maximizing approach. (I think it’s important to be transparent when recommending the latter, just because I take it many people are not in fact so comfortable with pursuing that strategy, even if I think they ought to be.)
Yeah. The words “estimates” and “about” are right there in the quote. There is no pretension of certainty here, unless you think mere use of numbers amounts to pretended certainty.
But what is decision relevant is the expected value. So by best estimate do they mean expected value, or maximum likelihood estimate, or something else? To my ear, “best estimate” sounds like it means the estimate most likely to be right, and not the mean of the probability distribution. For instance, take the (B) option in “Why it can be OK to predictably lose”, where you have a 1% chance of saving 1000 people, and a 99% chance of saving no one, and the choice is non-repeatable. I would think the “best estimate” of the effectiveness of option (B) is that you will save 0 lives. But what matters for decision making is the expected value which is 10 lives.
Sorry if this is a stupid question, I’m not very familiar with GiveWell.
Fair question! I don’t know the answer. But I’d be surprised if the two came apart too sharply in this case (even though, as you rightly note, they can drastically diverge in principle). My sense is that GiveWell aims to recommend relatively “safe” bets, rather than a “hits-based” EV-maximizing approach. (I think it’s important to be transparent when recommending the latter, just because I take it many people are not in fact so comfortable with pursuing that strategy, even if I think they ought to be.)