The Hicks-Malinvaud average period of production and 'marginal productivity': a critical assessment

Malinvaud (2003) observed that once techniques are ranked according to Hick’s concept of average period for a given rate of interest, a rise in the latter entails the use of a technique with a shorter average period. After a reconstruction of Malinvaud’s argument, it is shown that the result is far less encouraging for neoclassical theory than it might seem. The most important problem is not the fact that change in the interest rate affects the average period associated with a technique, despite the concern this aroused in Hicks and Malinvaud, but rather that it affects the ranking of techniques.