Yes, that's certainly true (for the record, most of my donations are to Givewell -- I particularly admire GiveDirectly as well -- and I think most charity shoul

Yes, that's certainly true (for the record, most of my donations are to Givewell -- I particularly admire GiveDirectly as well -- and I think most charity should go directly to where it's most needed). But there are exceptions -- for example, investing in (relatively already wealthy) health research industries (e.g. addressing pandemics) can save lives in the long run (indirectly), and I think some educational efforts and reserving a small part of your donations to local issues is effective. Diversification is a good idea in this case because I don't have time to measure some of those impacts precisely; otherwise I'd give everything to the most effective cause.