Hi all,,

I am getting inconsistent results and hope that someone can help me understand the source.
I have panel data and am looking at oil revenue's effect on human rights. I have human rights index (HRI) as dependent variable, oil revenue as main explanatory variable and I also have a binary variable (democracy) that is equal to 1 for democracies and 0 for autocracies. When i run a model :

1) xtreg HRI oil democracy oil#democracy
2)xtreg HRI oil if democracy ==0

I should get the same coefficient for oil which is the effect of oil for autocracies but I get different coefficient and statistical significance also varies. I tries several datasets (both cross sectional and panel including one available from Stata) and as expected the coefficients are the same but in my dataset I end up getting different coefficients. My only explanation might be that oil variables has many zeros but I even created a dataset with many zero values and as is expected i got the same results

Thank you in advance for your help