April 21, 2015

Dartmouth College and University of Virginia School of Law researchers have brought sophisticated computational techniques to a debate initiated by former Chief Justice William Rehnquist when he was a young attorney in private practice: What is the influence of the recent law grads who serve as judicial clerks on the U.S. Supreme Court?

The Dartmouth-UVA team looked for that influence by tracing the writing style of the justices. The researchers found that as clerks took on a more important role on the court, the justices’ individual writing styles became less consistent, presumably because the pool of clerks turns over each year. At the same time, the individual differences between justices diminished, leading to greater institutional writing style consistency on the court.

The research, which is the first computational analysis of general writing style ever conducted on all Supreme Court cases, also revealed that justices’ opinions are grumpier and wordier now than in the past, but that they are also easier to understand than their predecessors. The study is available on the Social Science Research Network and is to be published in the Washington University Law Review. A PDF also is available upon request.

“The opinions of the U.S. Supreme Court can have profound legal consequences, but they are also a major contributor to the genre of English legal writing,” says co-author Dan Rockmore, a professor of mathematics and computer science at Dartmouth who, in an earlier paper, used similar techniques to examine the evolution of writing style in the body of English literature. “In this study, we focus on the court’s role as an author rather than as a legal decision-maker.”

The Dartmouth-UVA researchers analyzed the frequency of function words, which has been found to be a useful “stylistic fingerprint” in a host of settings, from determining the authors of the Federalist Papers — one of the most important set of documents created during the founding of the United States — to forensic identification of criminal suspects, says co-author Keith Carlson, a Dartmouth PhD student in computer science.

“It would take about 12 years of full-time labor reading one opinion per hour to work through the entire body of Supreme Court decisions -- a task that could be held to be ‘cruel and unusual ‘ under the Eighth Amendment if assigned as punishment,” says co-author Michael Livermore, an associate professor of law at UVA.  “Advances in mathematics and computer science allow us to approach these massive textual datasets and perceive patters that no human could, or would want to, find on their own.”

The study found that:

• Law clerks have increased the consistency of writing style of the court as an institution, but have reduced the consistency of the individual justices;
• Highly cited justices don’t appear to exert greater stylistic influence;
• Modern justices write more similarly to their peers than to earlier justices;
• Modern justices tend to produce more words than their predecessors;
• Modern justices’ opinions are grumpier – or much less “friendly” (the percentage of positive versus negative words) -- than the opinions of earlier justices;
•  Modern justices’ opinions are written at a lower grade level than the opinions of their predecessors.

Available to comment are co-authors:

• Dartmouth Professor Dan Rockmore at daniel.n.rockmore@dartmouth.edu.
• UVA Law Associate Professor Michael Livermore at mlivermore@virginia.edu.