The Barnett critique, named for the work of William A. Barnett in monetary economics, argues that internal inconsistency between the aggregation theory used to produce monetary aggregates and the economic theory used to produce the models within which the aggregates are used are responsible for the appearance of unstable demand and supply for money. The Barnett critique has produced a long and growing literature on monetary aggregation and index number theory and the use of the resulting aggregates in econometric modeling and monetary policy.