I think I remember reading somewhere about how it costs much less to double the wellbeing of people in extreme poverty than it is to double the wellbeing with higher incomes. I don’t remember where I read that though. Can anybody point me articles or reports on this topic? I’d be especially interested to see good studies that put some numbers to this and/or reports (from GiveWell maybe?) about how specific charities improve wellbeing.
Somewhat low-effort answer:
I know Doing Good Better mentions the logarithmic relationship between income and wellbeing in one of its earlier chapters.
Relevant posts/articles:
https://ourworldindata.org/happiness-and-life-satisfaction#looking-across-and-within-countries
https://forum.effectivealtruism.org/posts/PPNgQSvKrcKvsM2ZN/the-effect-of-cash-transfers-on-subjective-well-being-and