Good evening,
I m a Vietnamese girl. I am really happy to meet you all.
I need your help on an issue when I am using statistical Stata.
My model includes one dependent variable is blg, independent variables are ful, eta, siz, liq, roa, inf, and gdp.
*** First, it is collinearity.
I sure that I check the correlation matrix of independent variables. There was no or low collinearity.
Like that: Array

And I also check again with command “Collin”.
With a low Vif and high tolerance, I conclude this model had no correlation. Array

But the matter comes out when I run GMM and LSDVC, approaches dropped two variables were inf and GDP because of collinearity. They were inflation rate and GDP growth rate in Vietnam. Array

When I ran in Eview with fixed effect or random effect, my model exported with sufficient variables. Of course, the correlation matrix with the coefficient is smaller than 0.9. Array

Why in Stata, my variables were dropped. Can you explain to me?
*** One more question, my model after dropping two variables, the resulting exports with no variables had significant. What ‘s the matter with my model. Should I give up this subject to do a new one? Array

Thanks for your help.
Trang