Ormerod and Mounfield (Physica A 293 (2001) 573) analyse GDP data of 17 leading capitalist economies from 1870 to 1994 and conclude that the frequency of the duration of recessions is consistent with a power law. But in fact the data is consistent with an exponential (Boltzmann–Gibbs) law.

A dynamic model of the social relations between workers and capitalists is introduced. The model self-organises into a dynamic equilibrium with statistical properties that are in close qualitative and in many cases quantitative agreement with a broad range of known empirical distributions of...