We analyze the rationalizability of variable-population social-choice functions in a welfaristframework. It is shown that xed-population rationalizability and a weakening ofcongruence together are necessary and suffcient for rational choice, given a plausible dominanceproperty that prevents the...

This note investigates the extension of Roberts' price-independent welfare prescriptions toalternatives in which population size and composition can vary. We show that ethicallyunsatisfactory orderings result. Suppose that a single person is to be added to a populationthat is unaected in utility...