Update 2021-10-06: I believe I was overconfident in my original interpretations of these Metaculus questions. Some commenters pointed out alternative interpretations of people's answers that could allow us to draw orthogonal or opposite conclusions. For example, on question 1, Metaculus users might predict GiveWell's top charities to drop off the list by 2031 not because better charities are discovered, but because current charities run out of room for more funding.
In the giving now vs. later debate, a conventional argument in favor of giving now is that people become better off over time, so money spent later will do less good. But some have argued the opposite: as time passes, we learn more about how to do good, and therefore we should give later. (Or, alternatively, we should use our money now to try to accelerate the learning rate.)
Metaculus provides some evidence that the second argument is the correct one: money spent later will do more good than money spent now.
This evidence comes from two Metaculus questions:
- Will one of GiveWell's 2019 top charities be estimated as the most cost-effective charity in 2031?
- How much will GiveWell guess it will cost to get an outcome as good as saving a life, at the end of 2031?
A brief explanation for each of these and why they matter:
On question 1: As of July 2021, Metaculus gives a 30% probability that one of GiveWell's 2019 top charities will be ranked as the most cost-effective charity in 2031. That means a 70% chance that the 2031 charity will not* be one of the 2019 recommendations. This could happen for two reasons: either the 2019 recommended charities run out of room for more funding, or GiveWell finds a charity that's better than any of the 2019 recommendations. This at least weakly suggests that Metaculus users expect GiveWell to improve its recommendations over time.
On question 2: Metaculus estimates that GiveWell's top charity in 2031 will need to spend $430 per life saved equivalent (according to GiveWell's own analysis). For comparison, in 2019, GiveWell estimated that its most cost-effective charity spends $592 per life saved equivalent. (These figures are adjusted for inflation.)
As with question 1, this does not unambiguously show that GiveWell top charities are expected to improve over time. Perhaps instead Metaculus expects GiveWell's estimate is currently too pessimistic, and it will converge on the true answer by 2031. But the cost reduction could also happen because GiveWell top charities truly get more effective over time.
Some caveats:
- These Metaculus answers only represent the opinions of forecasters, not any formal analysis. (Some forecasters may have incorporated formal analyses into their predictions.)
- Neither question directly asks whether money spent in 2031 will do more good than money spent now. (I don't know how to operationalize a direct question like that. Please tell me if you have any ideas.)
- These questions only ask about GiveWell top charities. Even if GiveWell recommendations become more effective over time, the same might not be true for other cause areas.
I think the third reason that you mention later is more likely, namely that "Perhaps instead Metaculus expects GiveWell's estimate is currently too pessimistic, and it will converge on the true answer by 2031."
This seems most likely to me since my guess is that the reason why GiveWell's estimate changed from $890 in 2016 to $436 in 2019 is because their methodology or something else changed (e.g. 2019-GiveWell thought 2016-GiveWell's way of estimating the "cost to get an outcome as good as saving a life" over-estimated the true cost). I don't think they actually believe the best giving opportunity was twice as cost-effective in 2019 as 2016. (I don't actually know this for sure, so if you or someone else knows better, please correct my guess.)
Does it? If "the 2019 recommended charities run out of room for more funding" this could be because e.g. governments or billionaires have stepped in to make sure that every child who needs one has a bed net and all deworming efforts have been fully funded forever. It seems to me that this would mean that the marginal philanthropist no longer has access to this low-hanging fruit. Since these opportunities would be fully-funded, GiveWell would then have to recommend the next best thing, which would be less cost-effective in expectation, not more.