Weinar's critique of GiveWell raises two sets of questions for me -- one on materiality, and one on deference.
Materiality
One strand of criticism relates to GiveWell possibly withholding information from donors to whom it is recommending charitable opportunities -- e.g., the number of lives lost as a result of the intervention. What standard would Weinar apply in determining whether a downside is sufficiently material that it needs to be disclosed to prospective donors? Also, does he think GiveWell et al. perform worse at disclosing potential downsides than other charities / charitable recommenders, or is this critique broadly applicable to charities writ large?
Another strand suggests that GiveWell hasn't done enough due diligence in investigating potential harms. (Arguably similar logic would apply for indirect benefits as well.) For GiveWell to do more research/analysis would presumably result in more money going to privileged Western insiders and less money going to work in developed countries. How should GiveWell decide when enough has been done?
My initial response to both strands would be that disclosure is material when there is a reasonable probability that disclosing information about downsides (plus any previously-undisclosed upsides of comparable magnitude) would change a significant number of donor decisions on where to donate. Likewise, further research would generally be material if there were a reasonable probability of changing GiveWell's recommendation or significant donor action. But one challenge here is: which donors? Do we look to donors who are roughly in alignment with GiveWell's basic moral framework? All potential donors in the country in which it is fundraising?
Deference
It seems almost inevitable that donors have to defer to someone. For a small-time donor like myself, travelling to research possibilities would consume my available budget. And there's no ex ante reason to think that people with more to donate are somehow more likely to intuit the correct donation opportunities themselves.
Weinar discusses the downsides that he perceives to deferring to GiveWell. One could instead defer to some version of Weinar's friend Aaron. But there are many different Aarons in the world; some would recommend good work, some would recommend poor work -- and Weinar seems to think a lot of foreign aid projects are problematic. I only know a few Aarons. If I went down this path, how worried should I be that none of my Aarons actually have good ideas, or that I am not very skilled at picking one of the better Aarons to defer to?
Likewise, there seems to be a suggestion that deferring to the people who live in the country is often a good idea. In the country where I live (the United States), a lot of local ideas about how to improve things are pretty bad. A glance at our political spectrum confirms that a significant majority of Americans agree that many ideas of at least 40% of other voters are pretty horrid (even though they disagree which ideas those are). I'd worry that a foreign donor deferring to some subset, or even some majorities, of the American people could easily make things considerably worse. How would Weinar suggest Western donors decide which local groups to defer to?
Your article concludes with an anecdote about your surfer friend Aaron who befriended a village and helped upgrade their water supply. Is this meant to be an alternative model of philanthropy? Would you really encourage people to do this on a large scale? How would you avoid this turning this into voluntourism, where poor people in the third world have to pretend to befriend wannabe white saviours in exchange for money?
And on a slightly more snarky note, for all the limitations of EA analysis, is it really worse at quantifying the positives and negatives than his pronouncements about projects' potential based on conversations with white Westerners in Bali? (that means both his well-intentioned surfer friend and the jaded twentysomethings enjoying drunken post-voluntourism R&R whose cynicism apparently transformed his entire view of the value of aid to people he never spent a moment talking to!)