I am analyzing the impact of price and promotion activities on sales in two separate 2-Way-Fixed Effects models. One model is for private labels, the other for national labels.

I now want to compare the coefficients of the two models with each other. My goal is to be able to state which type of price and promotion activity has a stronger effect for which brand.

Can anyone suggest an appropriate method? For linear models I found the Chow Test.

Thank you very much in advance"