Hello Friends,

My name is Goel Miranda, right now im trying to estimate a gravity equation for bilateral exports ( panel data) , the period of my panel is from 1948 to 2015. One of my independent variable "the experience exporting" ( exp_arcsin) and is a endogenous variable . I want to use a IV TOBIT and i have two instruments for this purpose .

This is my code without fixed effects

Code:
ivtobit ln_export2 ln_pbi_o ln_pbi_d ln_dist contig comlang_off colony gatt_d fta_wto  (exp_arcsin = exp_same_arcsin exp_idioma_arcsin ),ll(0)
i got this results:
Array




Then i run mi code with bilateral and time fixed effects (id_dum* year_dum*)


Code:
ivtobit ln_export2 ln_pbi_o ln_pbi_d ln_dist contig comlang_off colony gatt_d fta_wto  id_dum* year_dum* (exp_arcsin = exp_same_arcsin exp_idioma_arcsin ),ll(0)
and i got no results


Array

Theres some way to fix this issue?

Thank you!!