Hi everyone, I'm new here.
I am working on my Ms.thesis. the topic related to DETERMINANTS AND POTENTIAL TRADE OF 25 BIGGEST COFFEE EXPORTERS. (25 exporters, 196 importers, 2001-2019)I have tried to use many methods to estimate the gravity model and the results as in the table bellow
For the linear estimator: I use the Ftest; Breusch and Pagan Lagrangian; Hausman test =>FEM is appreciated, but the H0 of RESET test is not rejected, so there is heteroskedasticity, the predicted values also not good ( the values of some countries is too big). Then I use the PPML model with 3 fixed effects Time-Exporter; Time-Importer and Time-Exporter-Importer
my question is:
- Can I use the Ramsey test to select the appreciated model? (for estimating potential (GAP between predict and actual)
- Can I use the coefficient to estimate the potential trade for an individual country to its importer? (EX: calculate the gap between prediction and actual of Vietnam to all the importers)
thank you so much
OLS FEM REM TOBIT PPML Importer fixed effect PPML Importer, exporter fixed effect PPML Importer, exporter, time fixed effect
VARIABLES ln(EX+0.0001) ln(EX+0.0001) ln(EX+0.0001) ln(EX+1) EX EX EX
log_GDPex 0.0970*** 0.322*** 0.364*** 0.464*** 1.621*** 1.041*** -0.181
(0.00920) (0.0764) (0.0279) (0.106) (0.118) (0.0790) (0.119)
log_GDPim 0.0666*** 2.516*** 0.651*** 3.115*** -0.00761 2.273*** 0.994***
(0.00902) (0.0695) (0.0282) (0.101) (0.00806) (0.152) (0.153)
log_prodpercap_ex2 -0.0180*** 0.0205*** 0.0123*** 0.0222*** 0.0284*** 0.0131*** 0.0104***
(0.00120) (0.00210) (0.00184) (0.00276) (0.00422) (0.00205) (0.00312)
log_prodpercap_im2 -0.150*** -0.0108*** -0.0515*** -0.00881** -0.0417*** -0.000655 -0.00206
(0.00134) (0.00284) (0.00245) (0.00380) (0.00193) (0.00320) (0.00331)
log_pop_ex 0.505*** 0.854 0.0593 1.683 5.761 4.574* 1.375
(0.0193) (1.204) (0.0668) (1.833) (5.197) (2.386) (1.802)
log_pop_im 1.056*** -0.765** 0.294*** -0.754 0.738*** 2.087** -1.261**
(0.0145) (0.308) (0.0473) (0.462) (0.0177) (0.951) (0.574)
log_dist -2.045*** -2.756*** -1.312*** -0.929*** -0.610*** -0.614***
(0.0302) (0.103) (0.0261) (0.0395) (0.0257) (0.0247)
contig 3.185*** 2.271*** 1.303*** 0.626*** 1.023*** 1.022***
(0.159) (0.566) (0.106) (0.0908) (0.0683) (0.0655)
comlang_off 0.241*** -0.0647 1.668*** -0.0870 -0.305*** -0.308***
(0.0594) (0.210) (0.0553) (0.0623) (0.0578) (0.0569)
landlock_ex -0.419*** -1.179*** -3.689 4.584 2.070 -1.540
(0.0674) (0.232) (2.902) (3.285) (1.512) (1.152)
landlock_im -4.061*** -4.056*** -3.189 -0.873*** -33.51*** -5.646**
(0.0524) (0.188) (2.302) (0.0610) (4.098) (2.774)
both_rta 2.952*** -0.351 0.942*** -0.268 3.644*** 0.692** 0.745***
(0.215) (0.243) (0.233) (0.272) (0.232) (0.269) (0.263)
one_rta 0.943*** -0.262 0.322 -0.194 1.890*** 0.343 0.419*
(0.215) (0.232) (0.225) (0.225) (0.222) (0.247) (0.243)
religion 0.836*** 0.182 0.103 -0.568*** -0.395*** -0.390***
(0.0643) (0.228) (0.0716) (0.0783) (0.0585) (0.0566)
Constant -19.66*** -83.03*** -13.72*** -94.87*** -155.5 -181.5*** -19.17
(0.503) (21.24) (1.494) (34.96) (99.45) (46.55) (35.27)
Observations 87,839 87,839 87,839 87,839 87,839 87,839 87,839
R-squared 0.341 0.034 0.155 0.668 0.702
RESET p-values 0.0000 0.0000 0.0000 0.0000 0.0000 0.1341 0.0003
Ftest 0.0000
Breusch and Pagan Lagrangian 0.0000
Hausman test 0.0000 0.0000
Number of pairid 4,736 4,736
Standard errors in parentheses
*** p<0.01, ** p<0.05, * p<0.1