Case
Such a ranking may sound important and valuable at first – especially to the legal laymen. However, the general relevance of decisions, i.e. their importance for the constitutional jurisprudence in total, is not a big asset. The overall relevance is hardly helpful when the constitutional court faces the task of selecting the relevant laws and precedents for deciding a specific case. It does not help the constitutional jurist when making normative judgments by looking back and forth between the facts of a case and the law or preceding cases. It is possible that such a ranking could be the starting point when searching for relevant precedents. However, for a jurist with knowledge of constitutional law, it seems more promising to consult articles, textbooks and especially commentaries. Further, it is to be considered that German constitutional thinking is deeply rooted in each individual fundamental right enshrined in the Grundgesetz (abbreviated: GG, the German constitution) and that precedents only have a subordinate function.
The hypothesis that the most cited decisions are the most relevant, may therefore be correct in general. However, there is limited practical value to it. An exception could arise when one wants to understand the constitutional law by the means of precedents. To understand certain areas of constitutional jurisprudence it might make sense to focus on specific clusters of decisions. Therefore, we need to change from the macro-level (as shown above) to the meso-level (sub-network) of the citation network.
2. The resulting clusters of decisions relate to certain areas of constitutional jurisprudence.
The coloured clusters of decisions are determined by a modularity algorithm (see e.g. Blondel et al., 2008). Decisions within a cluster are stronger connected among each other than with decisions from other clusters. And in fact, the clusters partly represent certain fields of constitutional law. The yellow cluster in the diagram (see above) can be linked mainly to the field of state organisation (»Staatsorganisationsrecht”), as well as the constitutional areas of election, political parties, and mandate. On the other hand, the green cluster seems to predominantly encompass decisions based on the fundamental rights regarding personality and communication. The red cluster mainly touches upon the areas of taxes, family, social benefits, and questions of equality. The contents of the blue cluster are freedom of occupation and entrepreneurship and other areas. Especially, for the latter two there is no clear-cut separation.
Additional cross-connections between these fields (i.e. not only caused by material legal similarity) could arise from common constitutional procedural problems, questions of standing and obligations regarding fundamental rights in general, but also overarching dogmatic questions (scope of protection [Schutzbereich] – interference [Eingriff] – justification [verfassungsrechtliche Rechtfertigung]) and alike. Time should also be considered as a factor, when explaining why a decision cites a certain case rather than directly referencing an older landmark decision.
The clusters themselves and especially some of their sub-clusters could be a starting point when tackling sub-fields of constitutional law by using precedents or when trying to locate a decision within the vast amount of jurisprudence. Such method could further prove helpful when trying to ascertain the legal-historical perspective on and the genealogy of certain dogmatic or doctrinal figures – whereas using only the respective literature for this, would turn out time-consuming. Network analysis cannot replace a more detailed look at the context and type of the citation. However, it can provide a useful first step to the matter. Including the chamber decisions of the BVerfG into the network could be further beneficial, as these are rarely the topic of academic legal discourse. To conclude, the network analysis of constitutional jurisprudence can never replace meticulous legal work with decisions, commentaries, articles, and monographs, but it does supplement this work with a valuable additional perspective especially in the fields of legal history and legal sociology.
Prof. Dr. Cornelius Puschmann conducted the preparation, visualisation, and analysis of data. We would like to thank Prof. Dr. Axel Tschentscher for his helpful comments and Hanna Soditt for her valuable help with the translation of this piece.