# How to calculate the coefficient of a dummy variable reference category?

I am currently building a regression model with numerous continuous, categorical (employing dummies) and interaction variables. I understand we must use k-1 dummies with one variable becoming the reference category and then the impact of the other dummies can be reported on relative to this reference category.

I would however like to specifically identify the coefficient for the reference category. In this instance the reference dummy will be the UK with the dependant being fund returns. I have 6 country dummies and at present I can only say (for example) German funds underperformed the UK by 3%. Could any of you please advise me on how to ascertain the specific coefficient value for a reference dummy variable so I may be able to say UK funds performed x% throughout the period?

• Could you supply a small sample of your data? – André.B May 14 at 21:15
• That coefficient is zero – kjetil b halvorsen May 14 at 22:23

This assumes, however, that there is no interaction term involving your categorical variable country. If there is, then your interpretation of the 3% coefficient for Germany is incomplete: it represents the difference between Germany and UK only at the reference values of all other categorical variables and at 0 values of all continuous variables. You must also add in the contributions of all the interaction terms to compare Germany and UK in any other scenario.