Our short series of contextual reposts continues:

Although the state Supreme Courts have not attracted anything near the level of study from academics engaged in empirical legal studies that the U.S. Supreme Courts and Federal Circuits have a number of different researchers have attempted to compare how influential the various state courts are for the development of American law. One of the first efforts was published in 1936 by Rodney L. Mott, “Judicial Influence” (30 Am. Pol. Sci. Rev. 295 (1936)). Using several different proxies for influence, including law professors’ rankings, reprinting of a court’s cases in casebooks, citations by other state Supreme Courts and citations by the U.S. Supreme Court, Mott concluded that the most influential state Supreme Courts between 1900 and 1936 were New York, Massachusetts, California and Illinois.

In 1981, Lawrence Friedman, Robert Kagan, Bliss Cartwright and Stanton Wheeler published “State Supreme Courts: A Century of Style and Citation” (33 Stan. L. Rev. 773 (1981)). Friedman and his colleagues assembled a database consisting of nearly 6,000 cases from sixteen state Supreme Courts spanning the years 1870-1970. Among other things, the authors counted the number of times each case had been cited by out-of-state courts as a rough proxy for the author court’s influence. As far back as the 1870-1880 period, California ranked third among all state Supreme Courts in the sample for out-of-state citations, behind only New York and Massachusetts. By the 1940-1970 period – not coincidentally, a period when the California Supreme Court was developing a national reputation for innovation with a string of landmark decisions under the leadership of Chief Justices Gibson, Traynor and Wright – California had moved into first place in out-of-state citations. Fully 92% of all California Supreme Court decisions in the sample were cited at least three times by out-of-state courts, and 26% were cited more than eight times.

Two years later, Professor Gregory Caldeira published “On the Reputation of State Supreme Courts” (5 Pol. Behav. 83 (1983)). Using a database limited to cases published in 1975, Professor Caldeira focused on citations by other state Supreme Courts to each state’s decisions as a proxy for influence. He concluded that the top-performing courts were California, New York and New Jersey. Professor Scott Comparato took a somewhat similar approach in 2002 with “On the Reputation of State Supreme Courts Revisited,” using a random sample of thirty cases from each state Supreme Court. Professor Comparato concluded that the Supreme Courts of California and New York were cited by out-of-state courts significantly more often than the Supreme Courts of any other state.

In 2007, Jake Dear and Edward W. Jessen published “‘Followed Rates’ and Leading State Cases, 1940-2005” (41 U.C. Davis L. Rev. 683 (2007)). Dear and Jessen attempted to determine which state Supreme Court’s decisions were most often “followed” by out-of-state courts, as that term is used by Shepherd’s. Dear and Jessen concluded that the California Supreme Court is the most often followed jurisdiction in the country by a significant margin, with 33% more decisions between 1940 and 2005 which were followed at least once by an out-of-state court than the second highest finisher, Washington. California’s lead lengthens when the authors limited the data to cases followed three or more times by out-of-state courts, or five or more times – California leads Washington 160 to 72 in terms of decisions followed three or more times, and 45 to 17 for five or more.

Two years after Dear and Jessen’s paper was published, Professors Eric A. Posner, Stephen J. Choi and G. Mitu Gulati published their effort to bring all the various measures together, “Judicial Evaluations and Information Forcing: Ranking State High Courts and Their Judges” (58 Duke Law Journal 1313 (2009)). The authors compared the state Supreme Courts by three standards: productivity, opinion quality and independence, using a database consisting of all the Supreme Courts’ decisions between 1998 and 2000. Proposing out-of-state citations as a proxy for “opinion quality,” the authors determined that California was the most often cited court by a wide margin, with 33.76 “citations per judge-year,” as compared to 22.40 for Delaware, the second-place finisher.

Image courtesy of Flickr by Ken Lund (no changes).