Koyck arrived at the geometric
distributed lag model via the adaptive expectations hypothesis. This same hypothesis
was employed later by Cagan (1956) in a study of demand for money in conditions of
hyperinflation, by Friedman (1957) in a study of consumption behaviour and by Nerlove
(1958a) in a study of the cobweb phenomenon. The geometric distributed lag model
was subsequently generalized by Solow (1960), Jorgenson (1966) and others, and was
extensively applied in empirical studies of investment and consumption behaviour. At
about the same time Almon (1965) provided a polynomial generalization of Fisher’s
(1937) arithmetic lag distribution which was later extended further by Shiller (1973).