This paper develops a general technique for the computation of comparative dynamics in perfect-foresight discrete-time models. The method developed here is both applicable and general; it can be used to analyze the effects of the perturbation of parameters on endogenous variables and the welfare of an economic system derived from more general multisector models. It is neither restricted to the system's dimensions nor restricted by the assumption of distinct eigenvalues in the system.

This article uses the Z -transform to develop a method for solving the linearised multidimensional discrete-time systems, which can be used to discuss the effects of policies on economy (including the welfare gains and initial effects on economy) raised by multi-sector perfect-foresight-discrete-time models. Our method is not restricted to the dimension of the dynamic system, and it can not only analyse the effect of permanent policy change on the economy but also can be used to analyse the effect of temporal policy change on the economy. As an application example, we analyse the effects of fiscal policy on the initial economy and social welfare in the discrete-time Uzawa--Lucas model.