I guess a more useful way to think about this for prospective funders is to move things about again. Given that you can exert c/x leverage over funds within Cause Y, then you’re justified in spending c to do so provided you can find some Cause Y such that the distribution of DALYs per dollar meets the condition...
Q0.9≥c100x+Q0.5
...which makes for a potentially nice rule of thumb. When assessing some Cause Y, you need only (“only”) identify a plausibly best or close-to-best opportunity, as well as the median one, and work from there.
Obviously this condition holds for any distribution and any set of quintiles, but the worked example above only indicates to me that it’s a plausible condition for the log-normal.
I guess a more useful way to think about this for prospective funders is to move things about again. Given that you can exert c/x leverage over funds within Cause Y, then you’re justified in spending c to do so provided you can find some Cause Y such that the distribution of DALYs per dollar meets the condition...
Q0.9≥c100x+Q0.5...which makes for a potentially nice rule of thumb. When assessing some Cause Y, you need only (“only”) identify a plausibly best or close-to-best opportunity, as well as the median one, and work from there.
Obviously this condition holds for any distribution and any set of quintiles, but the worked example above only indicates to me that it’s a plausible condition for the log-normal.