It can be seen that the empirical model works much better in western Germany and that the explanatory power of the variables used is mixed: On the one hand, most of the explanatory variables are statistically significantly related to the probability of being a union member in at least one of the years covered (the exception being the variable indicating whether or not an employee holds a polytech or university degree).
exploredata-ZA2140_VarV147 exploredata-ZA3762_VarV688 exploredata-ZA3762_VarV670 exploredata-ZA2140_VarV401 exploredata-ZA3762_VarV3