If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.
If someone is saying "I saved 10 lives" because they gave $500 to a charity that advertises a cost per life saved of $50, then yes, that's very different from actually saving lives. But the problem is that charities' reports of their cost effectiveness are ridiculously exaggerated, and you just shouldn't trust anything they say.
What we want are marginal costs, not average costs, and these are what organizations like GiveWell try to estimate.
Yes, this is real. But we're ok with assigning credit along longish causal chains in many domains; why exclude charity?
Oh, trust me, I don't :-D
The problem with marginal costs is that they are conditional. For example, the marginal benefit of your $1000 contribution depends on whether someone made a $1m contribution around the same time.
I don't know about that -- I'm wary of assigning credit "along longish causal chains", charity is not an exception for me.