June 13, 2020
The field of welfare economics is associated with two fundamental theorems. The first states that given certain assumptions, competitive markets produce (Pareto) efficient outcomes; it captures the logic of Adam Smith’s invisible hand. The second states that given further restrictions, any Pareto efficient outcome can be supported as a competitive market equilibrium. Thus a social planner could use a social welfare function to pick the most equitable efficient outcome, then use lump sum transfers followed by competitive trade to bring it about. Because of welfare economics’ close ties to social choice theory, Arrow’s impossibility theorem is sometimes listed as a third fundamental theorem. A typical methodology begins with the derivation (or assumption) of a social welfare function, which can then be used to rank economically feasible allocations of resources in terms of the social welfare they entail. Such functions typically include measures of economic efficiency and equity, though more recent attempts to quantify social welfare have included a broader range of measures including economic freedom (as in the capability approach).
Updated Jun, 14 2020