A post by Dave Hoffman at PrawfsBlawg reminds me of Tom Smith's very cool draft article on SSRN that I have been meaning to mention: The Web of Law.

  Smith's article looks at legal citations from the standpoint of network theory, and presents the results of a citation study performed on Tom's behalf by the people at Lexis Nexis that looked at the citation structure of nearly 4 million American legal precedents. According to Smith, the study reveals that the citation of legal precedents creates a scale-free network, and that allows for all sorts of modeling from network theory that can shed light on legal dynamics. From the introduction:

  What determines whether a case makes it into the elite of cases that are cited hundreds or thousands of times, instead of just a few, or never? By studying the statistical dynamics of citation over time, scholars using network theory could shed significant light on what accounts for the success of a legal authority. How much, for example, does a case's merely being decided earlier account for its citation frequency? How much of a difference does a case having been decided by a higher court make? What about the "fitness" of a case, in terms of its persuasiveness or analytical acuity? Do these attributes explain in part a case's flourishing, survival, or extinction as a precedent? Do cases have a natural life span? Does their authority tend to wax and wane, and does this depend on the type of case? It is possible that if we study the evolution of the legal network, the "Web of Law," we will discover unsuspected historical dynamics in legal authority. Perhaps the characteristics of legal evolution themselves have changed over time. If there have been changes in the dynamics of legal evolution, or other noticeable changes, perhaps they correspond to recognized watersheds in legal history. As I discuss briefly below, using network theory to analyze law may enable us to understand, in a much more rigorous way than previously possible, the dynamics by which interpretations of important laws, such as the Constitution and landmark statutes, change over time.

  Very interesting stuff, and also both well-written and relatively short (with lots of cool graphs, too). I'll enable comments in case readers want to discuss the argument.