This study analyzes the stability of the distance coefficient values over time in the generalized gravity equation of Bergstrand (1989) using both aggregate and disaggregated trade flows among 22 OECD countries recorded for the sample period covering 1970 until 2000. We estimate the gravity...

We present a gravity model that accounts for multilateral resistance, firm heterogeneity and country-selectioninto trade, while accommodating asymmetries in trade flows. A new equation for the proportion of exporting…firms takes a gravity form: the extensive margin is also accected by...