Arepo's Quick takes

Suppose we compare two nonprofit orgs doing related work. Let’s use some real examples: Rethink Priorities and Founders Pledge, both of who do global health and climate change research; CEA (who run EAGs) and any community groups who run EAGxes; perhaps CFAR and Khan Academy.

Ideally, in an effectiveness-minded movement, every donation to one of them rather than the other should express some view on the relative capability of that org to execute its priorities - it is essentially a bet that that org will make better use of its money.

We can use a simple combinatorial argument to show that the epistemic value of this view rapidly approaches 0, the more things either or both of those organisations are doing. If AlphaOrg does only project A₁, and BetaOrg does only project B₁ (and for the sake of simplicity, that both projects are have the same focus) then donating to Alphaorg clearly shows that you think Alphaorg will execute it better - that A₁ > B₁.

But if Alphaorg adds a single (related or unrelated) project, A₂, to their roster, the strength of the signal drops to 1/6th: now in donating to Alphaorg, I might be expressing the view that A₁ > B₁ > A₂, that A₂ > B₁ > A₁, that A₁ > A₂ > B₁, or that A₂ > A₁ > B₁, or (if I think the lesser projects sum to more than the greater one), that B₁ >A₂ > A₁ or B₁ >A₁ > A₂. 

In general, the number of possible preference orderings we can have between just two orgs respectively running m and n projects between them is (m + n)![^end] (meaning 3*2=6 for three, 4*6=24 for four, 5*24=120 for five, and so on). If we also have GammaOrg with k projects of its own in the comparison, then we have (m + n + k)! possible preference orderings.

Assuming a typical EA org receives money from a couple of hundred donors a year, each of which we might consider a ‘vote’ or endorsement, that means on naive accounting (where we divide votes by preference orderings), as few as 6 projects between two relevant orgs give us less than a single endorsement’s worth of info on which of their projects effectiveness-minded donors actually support.

Obviously there are other considerations. Reduced administrative burden from combining is perhaps the foremost; also major donations can be restricted, somewhat mimicking the effect of donating to a more focused org (though if the org also receives unrestricted donations, it can undo this effect by just redirecting the unrestricted money) ; also one might want a very strong team to expand their focus on priors - though doing so would strongly reduce our confidence that they remain a strong team for the expanded purpose. 

Nonetheless, with the central EA orgs typically having at least 3 or 4 focus areas each (giving ~40320 possible preference orderings between two of them), and more if you count in-house support work - software development, marketing etc - as separate projects, I think the magnitude of this epistemic cost is something a purportedly effectiveness-minded and data-driven movement should consider very seriously.

[^end] To be precise, (k + n)! - 1 if they have the same number of projects, since we can exclude the case where you think every single one of Alphaorg’s projects is better than every single one of Betaorg’s.