i am doing my study gravity model in trade- a panel data analysis. one of the independent variable is DYPijt which denotes the absolute difference between country i's GDP per capita and country j‟s GDP per capita. the value of DYPijt in my study is negative. i am using log linear form how can i get the natural log of a negative value?
You would have to invent a new type of math. Natural logs are positive only.
If ALL of the values are negative, you should be able to compute an acceptable model driver. Compute the log of the absolute value instead but be sure to adjust for that calculation in your final equation.
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