Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Dialogue on Donation Splitting, published by JP Addison on November 29, 2023 on The Effective Altruism Forum.

I'll start us off with the standard argument against donation splitting. We'll start with the (important!) assumption that you are trying to maximize[1] the amount of good you can do with your money. We'll also take for the moment that you are a small donor giving <$100k/year.

There is some charity that can use your first dollar to do the most good. The basic question that this line of argument takes is: is there some amount of money within your donation budget that will cause the marginal effectiveness of a dollar to that charity to fall below that of the second best charity.

For example, you could imagine that Acme Charity has a program that has only a $50k funding gap. After that, donations to Acme Charity would go towards another program.

The standard argument against donation splitting, which seems right to me, is that the answer to that question is "probably not."

[1]: Most definitions of effective altruism have language about maximizing ("as much as possible"). I personally do make some fuzzies-based donations, but do not count them towards my Giving What We Can Pledge.

Here's the donation splitting policy that I might argue for: instead of "donate to the charity that looks best to you", I'd argue for "donate to charities in the proportion that, if all like-minded EAs donated their money in that proportion, the outcome would be best".

Here's the basic shape of my argument: suppose there are 1000 EAs, each of which will donate $1000. Suppose further there are two charities, A and B, and that the EAs are in agreement that (1) both A and B are high-quality charities; (2) A is better than B on the current margin; but (3) A will hit diminishing returns after a few hundred thousand dollars, such that the optimal allocation of the total $1M is $700k to A and $300k to B.

Donate $700 to A and $300 to B (donation splitting); or

Don't donate all at the same time. Instead, over the course of giving season, keep careful track of how much A and B have received, and donate to whichever one is best on the margin. (In practice this will mean that the first few hundred thousand donations go to A, and then A and B will each be receiving donations in some ratio such that they remain equally good on the margin.)

But if you don't have running counters of how much has been donated to A and B, the first policy is easier to implement. And both policies are better than the outcome where every EA reasons that A is better on the margin and all $1M goes to A.

Now, of course EAs are not a monolith and they have different views about which charities are good. But I observe that in practice, EAs' judgments are really correlated. Like I think it's pretty realistic to have a situation in which a large fraction of EAs agree that some charity A is the best in a cause area, with B a close second. (Is this true for AMF and Malaria Consortium, in some order?) And in such a situation, I'd rather that EAs have a policy that causes some fraction to be allocated to B, than a policy that causes all the money to be allocated to A.

Note that how this policy plays out in practice really does depend on how correlated your judgments are to those of other EAs. If I'm wrong and EAs' judgments are not very correlated, then donating all your budget to the charity that looks best to you seems like a good policy.

I like this position - I'm already not sure how much I disagree. Some objections that might be more devil's advocate-y or might be real objections:

I agree correlation is important. I'm not sure how to define it and, once defined, whether it will be correlated enough in practice.

Roughly speaking, what decision theory / unit of analysis are we using here? It seems like your opening statement assum...