The Aggregate Production Function: 'Not Even Wrong'

The foundations of the aggregate production function were long ago thrown into doubt by problems of aggregation and the Cambridge capital theory controversies. Yet the aggregate production function, whether in the familiar form of the Cobb-Douglas, the CES, or the translog, continues to be widely used in both theoretical and applied analysis. The reason for its continued use rests on the instrumental position that 'it works'. The aggregate production function sometimes yields good statistical fits with plausible estimates of the coefficients. However, for some time, it has been realised that the existence of an underlying accounting identity can explain the regression results, even if the aggregate production function does not exist. This argument has been widely ignored. This paper, drawing on a rhetorical approach, assesses why this is the case. It shows that the few criticisms that have been made of the critique involve fundamental misunderstandings that represent a failure of the economic method.