Hi Nick! Thanks so much for your thoughtful response. Here are some of our thoughts on your questions:
**Have you reached out directly to Evidence Action and GiveWell to ask about why they went so hard on chlorination and not ceramic filters? **
Your assumption here that there is a direct connection between cases of diarrhoea and mortality. We have very little clue why clean water leads to a mortality reduction, so I'm not sure its reasonable to make the leap, first that there is a causal relationship at all between diarrhoea reduction and the huge mortality reduction, and second that that connection moves linearly like is assumed here (For every % of diarrhoea reduction, mills-reincke effect moves the same).
**I could be wrong but I'm not sure there's any good data at all on mortality reductions for clean water in over 5s. **The Kremer study Is the only one I know which looks directly at mortality at all, and then only in under 5s. Where does this number come from? My intuition would that the multiplier should be far smaller than this (very very uncertain).
I think 2 years is ambitious number for lifespan. Between families neglecting to use it (perhaps most important) kids breaking, families selling it (not the end of the world), dirty water clogging it etc. I would have perhaps gone for 1 or 1.5 years use as realistic, but this isn't so important. I struggled in a 5 minute search to find decent research on ceramic filter lifespan in the real world, do you have one?"
From my experience it is borderline implausible that 5.8% of diarrhoeal episodes lead to hospitalisation
Also quick correction I think you mean the $8 country is Nigeria here.
Again, thank you so much for your thoughtful response.