Multiplier Comparisons of the IMPLAN and REMI Models across Versions: Illuminating Black Boxes

Despite the widespread use and several published evaluations of the IMPLAN and REMI models, the issue of how the multipliers in these models compare is unresolved. In particular, little is known about the stability of the IMPLAN and REMI multipliers across the different versions of the models. The difficulty in comparing the multipliers derives from problems in benchmarking or standardizing the models, and this problem has been compounded by the release of new versions in recent years. Therefore, in this paper the current and previous versions of the IMPLAN and REMI models are compared. It is found that apparent changes in the multipliers in each model result from undocumented or poorly documented changes in the vendor default values of the available options for calculating the multipliers, not from structural changes in the models. The use of benchmarked versions of each model in the comparison, then, provides evidence on the stability of the multipliers of the models, and forms the basis for clarifying the misinterpretations of results in some of the published evaluations.