The German economy is not only affected by unification of Germany but by a significant influx of immigrants from abroad and huge migration from East to West Germany around the date of unification. Data from the German Socio-Economic Panel Study (GSOEP) allows one to disentangle those effects by decomposition of the Theil I(0)-Index of inequality. In addition, the paper offers insights into the transition from a socalist economy into a market oriented one.
Grabka, M. M., Schwarze, J., & Wagner, G. G. (1999). How unification and immigration affected the German income distribution. European Economic Review, 43(4–6), 867–878. https://doi.org/10.1016/S0014-2921(98)00100-7