The distinction between transitory and permanent shocks is at the centre of the debate on which class of models is best suited to represent economic variables: stationary models around a deterministic trend, or stationary models around a stochastic trend The debate u here focused on the Australian case. It is found that both aggregate output and consumption are characterized by stochastic trends, but without a transitory component This corresponds to a measure of shock persistence equal to one for both variables. For the specific case of aggregate output, this result may be interpreted as indicating the absence of business cycles