I think this suggests the cause prioritization factors should ideally take the size of the marginal investment we’re prepared to make into account, so Neglectedness should be
“% increase in resources / extra investment of size X”
instead of
“% increase in resources / extra person or $”,
since the latter assumes a small investment. At the margin, a small investment in a neglected cause has little impact because of setup costs (so Solvability/Tractability is low), but a large investment might get us past the setup costs and into better returns (so Solvability/Tractability is higher).
As you suggest, if you’re spreading too thin between neglected causes, you don’t get far past their setup costs, and Solvability/Tractability remains lower for each than if you’d just chosen a smaller number to invest in.
I think this suggests the cause prioritization factors should ideally take the size of the marginal investment we’re prepared to make into account, so Neglectedness should be
“% increase in resources / extra investment of size X”
instead of
“% increase in resources / extra person or $”,
since the latter assumes a small investment. At the margin, a small investment in a neglected cause has little impact because of setup costs (so Solvability/Tractability is low), but a large investment might get us past the setup costs and into better returns (so Solvability/Tractability is higher).
As you suggest, if you’re spreading too thin between neglected causes, you don’t get far past their setup costs, and Solvability/Tractability remains lower for each than if you’d just chosen a smaller number to invest in.