Comparison of Input–Output,Input–Output + Econometric and Computable General Equilibrium Impact Models at the Regional Level

Economic impact studies are a common practice—indeed, a necessary prerequisite in many cases of project development—in Australia. Although input–output (IO) is still regarded as the ‘bread-and-butter’ model for these types of study, attention in recent years has turned towards more sophisticated models, the main contenders being integrated IO + econometric and computable general equilibrium models. All these models, which are often promoted as substitutes, exhibit characteristics which are theoretically and empirically appealing, yet questions have been raised with respect to the different approaches, with apparently little awareness at the practitioner level as to the extent of these differences. This paper compares the three models and demonstrates that the differences can be quite substantial, even when the models rely on the same database and are subjected to the same impact scenario.