I’d guess it’s because it’s very hard to apply a GiveWell approach (i.e. explicit quantitative modeling based on a substantial body of empirical evidence) to many long-termist orgs (whose impacts will often definitionally be unknown for the foreseeable future, and around which there is large and pervasive uncertainty). Open Philanthropy describes an evaluation methodology that seems more suited to long-termist orgs.
I’d guess it’s because it’s very hard to apply a GiveWell approach (i.e. explicit quantitative modeling based on a substantial body of empirical evidence) to many long-termist orgs (whose impacts will often definitionally be unknown for the foreseeable future, and around which there is large and pervasive uncertainty). Open Philanthropy describes an evaluation methodology that seems more suited to long-termist orgs.