This paper seeks to quantitatively assess the key role in open economy of heterogeneity in the conduct of monetary policy in Europe and the US, we take into account the fact that these two economies trade with each other and with the rest of the world, as well as the role of the exchange rate in trade. Using Bayesian estimation techniques, we estimate two models that take these specific features into account, a model with representative agents (RANK model), a model with heterogeneous agents (TANK model). Analysis of the Bayes ratio and the empirical characteristics of the two models shows that the TANK model plays a key role in the conduct of monetary policy in Europe and the United States and in the mitigation of cycles and fluctuations. The American economy is more sensitive to heterogeneity than the European one, because the differences in parameters between the models are greater in the USA than in Europe.
JEL Classification: E21 , E31 , E40 , E50 , E52 , E61