Keynes after Sraffa and Kaldor: Effective demand, accumulation and productivity growth

This paper analyzes to what extent John Maynard Keynes was successful in showing that the economic system tends to fluctuate around a position of equilibrium below full employment in the long run. It is argued that a successful extension of Keynes's principle of effective demand to the long run requires the understanding of the contributions by Piero Sraffa and Nicholas Kaldor. Sraffa provides the basis for the proper dismissal of the natural rate of interest, while the incorporation by Kaldor of the supermultiplier and Verdoorn's Law allows for a theory of the rate of change of the capacity limit of the economy.