Sen showed how to study various assumptions concerning the measurability and interpersonal comparability of utilities by coordinating the social orderings derived from profiles that, depending on these assumptions, carry the same information. For instance, ordinal measurement with interpersonal noncomparability—built by Arrow right into his technical framework—amounts, in Sen’s more flexible set up, to a requirement that the same social ordering is to be derived from any utility profiles that reduce to the same list of orderings. At the other extreme, utilities are measured on a ratio scale with full interpersonal comparability if those profiles yield the same social ordering that can be obtained from each other by rescaling, or multiplying all utility functions by the same positive real number. Sen explored different combinations of such assumptions.