Is the Output Growth Rate in NIPA a Welfare Measure?

Abstract

Bridging modern macroeconomics and the economic theory of index numbers, this paper shows that real output growth as measured by National Income and Product Accounts (NIPA) is a welfare based measure. In a two-sector dynamic general equilibrium model of heterogeneous households, recursive preferences and quasi-concave technology, individual welfare depends on present and future consumption. In this context, the Bellman equation provides a representation of preferences over current consumption and investment. Applying standard index number theory to this representation of preferences, it is shown that the Fisher-Shell true quantity index is equal to the Divisia index in turn well approximated by the Fisher ideal chain index used in NIPA.