Hello, I have to do a counterfactual analysis I need to see how the unemployment rate of a country like Poland would have been if Poland had not joined the European Union so i have data between 1998 a

Hello, I have to do a counterfactual analysis

I need to see how the unemployment rate of a country like Poland would have been if Poland had not joined the European Union so

i have data between 1998 and 2015 for poland , i have to do a counterfactual analysis for see if Poland had not joined the European Union in 2004 what would have happened on data from 2004 to 2010

and I would like to know what the calculations are