Gravity 2023

library(readxl)
gravity <- read_excel("gravity.xlsx")

gravity$limports<-log(gravity$imports)
gravity$lgdp_exporter<-log(gravity$gdp_exporter)
gravity$lgdp_importer<-log(gravity$gdp_importer)
gravity$ldist<-log(gravity$dist)

gravity2<-subset(gravity,gravity$imports>0)


#install.packages("estimatr")
library(estimatr)
ols<-lm_robust(gravity2$limports ~ gravity2$lgdp_exporter + gravity2$lgdp_importer + gravity2$ldist + gravity2$comlang_off)
summary(ols)

## 
## Call:
## lm_robust(formula = gravity2$limports ~ gravity2$lgdp_exporter + 
##     gravity2$lgdp_importer + gravity2$ldist + gravity2$comlang_off)
## 
## Standard error type:  HC2 
## 
## Coefficients:
##                        Estimate Std. Error t value   Pr(>|t|) CI Lower CI Upper
## (Intercept)             -33.751   0.352954  -95.63  0.000e+00 -34.4433 -33.0596
## gravity2$lgdp_exporter    1.226   0.007648  160.29  0.000e+00   1.2108   1.2408
## gravity2$lgdp_importer    0.951   0.007571  125.61  0.000e+00   0.9361   0.9658
## gravity2$ldist           -1.374   0.020435  -67.24  0.000e+00  -1.4141  -1.3340
## gravity2$comlang_off      1.293   0.050422   25.65 8.613e-143   1.1945   1.3922
##                           DF
## (Intercept)            19973
## gravity2$lgdp_exporter 19973
## gravity2$lgdp_importer 19973
## gravity2$ldist         19973
## gravity2$comlang_off   19973
## 
## Multiple R-squared:  0.6424 ,    Adjusted R-squared:  0.6423 
## F-statistic:  9877 on 4 and 19973 DF,  p-value: < 2.2e-16