In common law jurisdictions such as the United States, courts frequently resolve disputes by citation and analysis of reports of prior legal cases. The law may thus be thought of as a giant network containing textual information embedded in cases (nodes) and relationship information called citations (arcs) going from node to node. In recent years, the science of studying networks has developed and, while there had been some rudimentary attempts to look at subsets of the vast legal network, until recently there had been little done to take advantage of modern technology and modern network theory in that effort.
The paper shows that fascinating results are to be found applying these new technologies and theories to case law; results that clearly beg for comparative analysis across jurisdictions. There are various measurements available, each of which covers different aspects of the network characteristics of case law. A first indicator is the relative frequency of citation of cases. Here the analysis comes up with, as the author says, a fairly predictable list of famous cases (Professor Chandler acknowledges the work of Thomas Smith - San Diego - who, in his paper The Web of Law, has found, for example, that 2% of the USSC's decisions make up for 96% of its case citations). The paper then goes on to determine the centrality of cases, based on their 'connectedness', their 'betweenness' and on whether they form part of a 'main core' of Supreme Court jurisprudence. 'Connectedness' is expressed as the 'distance' between cases, measured as the number of steps through citations required to get from any one decision to the specified case). 'In betweenness' of cases is based on the frequency a decision appears on citation-trajectories between other cases. The final mode of analysis looks for the 'main core' of Supreme Court jurisprudence, consisting of a group of cases with a certain minimum number of connections to other cases within in the same group).
Based on these various measurements, the author concludes that 'structural cases' "involving the role of the federal courts" figure at the core of the Supreme Court's case law in that they lie extremely close to other decisions. The density of connections between decisions is very high in free speech and assocation cases. This would mean that in this area "reinterpretations of a particular case are likely to reverberate significantly" throughout the system.
Highly recommended. Watch for further results from Houston!
Seth J. Chandler
The Network Structure of Supreme Court Jurisprudence
Document: Available through SSRN