5Currently 402 districts and urban districts exist in Germany. Unfortunately, and due to the data structure at the local registers, the data on voluntary organizations could not be provided separately for 24 districts and urban districts. 12 units of analysis thereby represent both “district” and “urban district”. A dummy variable is included to control for the arbitrary nature of these units, indicating these 12 hybrid units in further analysis. For this reason, the number of units in the following analysis is reduced to 390.