Abstract: | This paper puts forward the proposition that failure to take account of stochastic seasonality results in dynamic misspecification. This point is illustrated by estimating various versions of a simple Australian consumpt ion function using seasonally unadjusted data covering the period 1959(3)–1993(3). It is demonstrated that only the equation modelling stochastic seasonality as an unobserved component shows no dynamic misspecification unlike other equations. This equation is also shown to have the highest explanatory power and, unlike other equations, to be structurally stable |