I am highly grateful to Alexey Morgunov and Adam Casey for reviewing and commenting on an earlier draft of this post, and pestering me into migrating the content from many emails to a somewhat coherent post.

Will Crouch has posted about the Centre for Effective Altruism and in a follow up post discussed questions in more detail. The general sense of the discussion of that post was that the arguments were convincing and that donating to CEA is a good idea. Recently, he visited Cambridge, primarily to discuss 80,000 hours, and several Cambridge LWers spoke with him. These discussions caused a number of us to substantially downgrade our estimates of the effectiveness of CEA, and made our concerns more concrete.