1. Gravity: a popular tool

2. Gravity: a recap

3. Standard proxies for trade costs

5. Initial equation estimated

6. Theoretical foundation: historical evolution

7. Technical derivation

11. Multilateral resistance: the intuition

12. Theoretically founded equation

13. Gravity specification of Multilateral trade resistance

14. Country fixed effects

15. Cross country equation (1 year) It is impossible to estimate the coefficient of GDP or other country specific variable

16. More than 1 year: panel data

17. Panel data: time-varying fixed effects

18. Estimating using country-pair fixed effects Random effects: use Hausman test in order to choose between random and fixed effects estimation

19. Recent theoretical developments

20. Data sources