Keith M. Carlson and Scott E. Hein compare the long-run characteristics of three well-known econometric models—Chase, DBI, and Wharton—to those of the St. Louis model. The purpose of this comparison is to determine whether the St. Louis model—an explicitly monetarist model—provides different implications about the long-run effects of monetary policy from those generated by non-monetarist econometric models. The comparisons were based on the impacts of four alternative monetary policy scenarios on simulations of a number of economic variables—including inflation rates, real GNP growth, and nominal GNP growth. The simulations from the four models cover the period from 1987 to 1991, which represents the last five years of a 10-year simulation for the 1982-91 period. These simulations were chosen to represent the “long-run” policy simulations; differences in the simulations across the models represent differences in the long-run characteristics of the models. These long-run simulations also were compared to the actual relationships between money growth and the same economic variables over the period from 1955 to 1981 to determine their consistency with the historical record. Significant deviations from the historical pattern is taken as evidence that there is some “problem” with the model’s ability to capture the long-run consequences of monetary policy actions.