Sub-national inter-parliamentary cooperation? Mapping Twitter networks of German state MPs

Inter-parliamentarism and inter-parliamentary cooperation is often studied on inter- or supranational levels, introducing a variety of intermediate variables to the inquiries. Studying inter-parliamentarism within a national state and between regional or state parliaments enables research with a multitude of more or less constant variables, such as societal or language effects or a shared and well understood overarching political system. Yet, even within a nation state as Germany with 16 state parliaments, data collection of parliamentary proceedings is unstandardised and extremely labor intensive. Therefore, this paper introduces inter-parliamentary networks of MPs in social media as a proxy for inter-parliamentary cooperation. Studying sub-national inter-parliamentarism seems to be a fruitful endeavour on many avenues and therefore mapping sub-national inter-parliamentary networks on Twitter is a useful task for descriptive statistics alone. However, this also brings up more structural and more quantifiable research questions, for example the role of capabilities and resources, touching on the question of division of labour within and between state parliaments. This analysis presents a new data set of 1632 Twitter accounts by 3102 members of all German state parliaments and all tweets and retweets between these actors made in the year 2021. It presents extensive descriptive statistics delineating structural variables such as state or party effects, for macro and micro predictors respectively. Furthermore, an inferential network analysis is performed using temporal exponential random graph models. Several configurations of party and state effects are significant, yet it is also evident that the incorporation of additional variables would benefit the explanation. Nonetheless is the presented model a suitable base model for further research endeavours. Studying sub-national inter-parliamentarism informs future work on inter-parliamentarism in more conventional contexts, since structural effects are more prominent due to the aforementioned constants. It provides a solid fundament for work on multilevel parliamentary cooperation and furthers our understanding of parliamentary networks in more societal settings. The rich and new data set on German Twitter networks is also a data source for a multitude of different research questions.