This paper uses a sectoral version of conventional Imperfect substitutes model to motivate a parsimonious estimation of trade elasticities. The elasticities we compute depend directly on the specialization of trade across sectors, which is believed to add econometric precision to our estimates....

Time series models are often fitted to the data without preliminary checks for stability of the mean and variance, conditions that may not hold in much economic and financial data, particularly over long periods. Ignoring such shifts may result in fitting models with spurious dynamics that lead...