Table 2.7 Panel regressions from estimating total bilateral trade with the extended gravity model, 1970–92

Note that the estimates of column 1 have slightly higher adjusted values of R2 and slightly lower mean square errors. The main point in Table 2.7 is to show that while some of the parameter estimates are somewhat sensitive to the differences in specification, the results are very similar between the two samples and in all cases the results show the general validity of the gravity model. We refer to the column 1 estimates as the base model and the column 4 ones as the extended gravity model.