The research findings presented here were generated in a research project funded by the German Research Foundation titled "Relationship between SPD and Greens at the Municipal Level." The scientific staff included Rainer Berger and Jörg Wischermann, while the student assistants were Ursula Kux and Lars Vogelsang, with Bodo Zeuner serving as the project leader. Rainer Berger was involved in the design, data collection, and analysis of the study at all stages. His focus was on combining the data from our survey with data on the social and economic structure of the municipalities, as well as the substantive goals and results of the cooperation between SPD and Greens in various policy areas. He is publishing a separate secondary analysis on this topic.