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The application of data analytic techniques to the study of judicial decision making arguably begins with political scientist Charles Grove Haines’ 1922 article in the Illinois Law Review, General Observations on the Effects of Personal, Political, and Economic Influences in the Decisions of Judges. (17 Ill. L. Rev. 96 (1922)). Reviewing the records of New York City magistrate courts, Haines noted that while 17,075 people had been charged with public intoxication in 1916 – 92% of whom had been convicted – one judge discharged just one of 566 cases, another 18%, and still another fully 54%. Haines argued from this data that results in the magistrate courts were reflecting to some degree the “temperament . . . personality . . . education, environment, and personal traits of the magistrates.”

Two decades later, another political scientist, C. Herman Pritchett published The Roosevelt Court: A Study in Judicial Politics and Values, 1937-1947. Pritchett became interested in the work of the Supreme Court when he noticed that the Justices’ dissent rate had sharply increased in the late 1930s. Pritchett argued that the increase in the dissent rate necessarily weighed against the formalist view that “the law” was an objective reality which appellate judges merely found and declared. In The Roosevelt Court, Pritchett published a series of charts showing how often various combinations of Justices had voted together in different types of cases (the precursor of the some of the analysis we’ll publish later this year in California Supreme Court Review).

Another landmark in the data analytic literature, the U.S. Supreme Court Database, traces its beginnings to the work of Professor Harold J. Spaeth about three decades ago. Professor Spaeth undertook to create a database which classified every vote by a Supreme Court Justice in every argued case for the past five decades. In the years that followed, Spaeth updated and expanded his database, and additional professors joined the groundbreaking effort. Today, thanks to the work of Professors Harold Spaeth, Jeffrey Segal, Lee Epstein and Sarah Benesh, the database contains 247 data points for every decision the U.S. Supreme Court has ever rendered – dating back to August 3, 1791.  The Supreme Court Database is a foundational tool utilized by nearly all empirical studies of U.S. Supreme Court decision making.

Not long after the beginnings of the Supreme Court Database, Professors Spaeth and Segal also wrote one of the landmarks of data-driven empirical research into appellate decision making: The Supreme Court and the Attitudinal Model, in which they proposed a model arguing that a judge’s personal characteristics – ideology, background, gender, and so on – and so-called “panel effects” – the impact of having judges of divergent backgrounds deciding cases together as a single, institutional decision maker – explained a great deal about appellate decision making.

The data analytic approach began to attract widespread notice in the appellate bar in 2013, with the publication of Judge Richard A. Posner and Professors Lee Epstein and William M. Landes’ The Behavior of Federal Judges: A Theoretical & Empirical Study of Rational Choice. Drawing upon arguments developed in Judge Posner’s 2008 book How Judges Think, Posner, Epstein and Landes applied various regression techniques to a theory of judicial decision making with its roots in microeconomic theory, discussing a wide variety of issues from the academic literature.

Today, there is an enormous academic literature studying the work of the U.S. Supreme Court and the Circuits from a data analytic perspective on a variety of different issues, including case selection, opinion assignment, dissent aversion, panel effects, the impact of ideology, race and gender. The state Supreme Courts have attracted somewhat less study than the federal appellate courts, but that has begun changing in the past several years.

In the months to come here at the California Supreme Court Review, we’ll apply many of the techniques pioneered and used in this academic literature to gain insights into every aspect of the work of the California Supreme Court.

Image courtesy of Flickr by Jamison Wieser (no changes).