Also, any new pledger has some non-zero chance of breaking the pledge (see the GWWC fundraising prospectus for their current estimates, though some people have argued these are under-estimates). The chance of different people is probably largely independent. If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and would probably lead to more money being moved (ie narrower 95% confidence interval on the amount moved).
“If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and thus have a higher expected value.”
I don’t think this is true, at least not taken naively. Ie, 70%20%=70%10%*2. Decreasing variance isn’t quite the same thing as expected value, and there are so many problems in the world that needs money that decreasing variance just isn’t that important relatively to channeling as much (expected) income as possible to the most effective causes.
Also, any new pledger has some non-zero chance of breaking the pledge (see the GWWC fundraising prospectus for their current estimates, though some people have argued these are under-estimates). The chance of different people is probably largely independent. If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and would probably lead to more money being moved (ie narrower 95% confidence interval on the amount moved).
“If this is true, then at the margin, two 10% pledgers have a lower chance of both defaulting and thus have a higher expected value.”
I don’t think this is true, at least not taken naively. Ie, 70%20%=70%10%*2. Decreasing variance isn’t quite the same thing as expected value, and there are so many problems in the world that needs money that decreasing variance just isn’t that important relatively to channeling as much (expected) income as possible to the most effective causes.