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...

The present paper studies the relationship between R&D investment and firm productivity growth by explicitly accounting for non-linearities in the R&D-productivity relationship and inter-sectoral firm heterogeneity. In order to address these issues, we employ a two step estimation approach, and...