Technical progress can be expected to reduce transport costs over time, yet most studies of bilateral trade based on the gravity model find distance effects to be increasing rather than decreasing. We investigate countries' openness to international trade (the ratio of exports plus imports to...

We review and interpret the main theoretical developments in the gravity literature from its very early, a-theoretical applications to the latest structural contributions. We also discuss challenges and implement methods to estimate empirical gravity equations. We finish with a presentation and...

Geographic distance plays an important role in many disciplines like economic geography, trade or demography. In international economics and finance, it is primarily used as a substitute of transaction costs in gravity equations of bilateral trade in goods and assets. This paper is a synthesis...