In our last post, we addressed the yearly average length of the Court’s opinions in civil cases for the year 1990 through 2003. Today, we’re looking at the years 2004 through 2017. In doing so, we’re looking for evidence on two questions: first, are opinions getting shorter or longer over time; and second, do longer dissents tend to mean longer majority opinions?
We report the yearly data for majorities, special concurrences and dissents in Table 957. Leaving aside the occasional two to three-year spikes and dips, the average majority opinion was about as long for the years 2004 through 2017 as it was in the first fourteen years of our period. For the years 2005 through 2007, majorities averaged 19.4, 21.73 and 17.93 pages. For the years 2014 and 2015, the average majority opinion in a civil case dropped below ten pages for the first time – 9.22 in 2014 and 9.8 in 2015.
Special concurrences were about where they were for the years 1990 to 2003 too. Other than a one-year spike in 2009 to 16.5 pages (the result of there being few concurrences in the set), special concurrences were in a narrow range from about three pages to nearly six pages long. (The gap in the trend line at 2015 signifies there having been no special concurrences that year in civil cases.)
Dissents, on the other hand, tended to be just a bit longer in these years. The average dissent was 7.12 pages in 2004, 8.14 in 2006, 7.08 in 2008, 8.1 in 2010 and 8.7 in 2011. After a short dip – 6.33 pages in 2012, 5.88 in 2013, 4.86 in 2014 and 5.78 in 2015 – dissents in civil cases got longer again, increasing to an average of nine pages in 2016 and 9.4 pages in 2017.
Despite the indications of a slight uptick in dissents, the Court’s average total output of opinions in civil cases remained relatively stable between 2004 and 2017. For the years 2005, 2006 and 2009, the Court was producing its largest volume of pages of the entire twenty-eight year period (35.08 pages, 33.37 and 38.36, respectively). But by 2012, the average civil case was producing only 19.61 pages of opinion. After two years around the same level – 19.94 in 2013 and 20.08 in 2014 – the average dropped to its lowest level in 2015 – 15.58 total pages. But in the two years since, opinions have gotten longer – 25.31 pages in 2016 and 26.94 pages in 2017.
At the outset, we asked whether longer dissents or special concurrences tended to result in longer majority opinions. To get a bit of further evidence on that question, we calculated the correlations for the years 1990-2017 between the average length of the Court’s civil majority opinions and their dissents, and the correlation between majorities and special concurrences. If more pages of dissents (or concurrences) tend to lead to more pages of majorities, the correlation should be higher. If not, the correlation should be lower. And of course, as every statistician always warns – mere correlation does not necessarily indicate causation. In civil cases since 1990, the correlation between the length of majority opinions and dissents is 0.4638 – not a strong relationship, but a moderate correlation, indicating that dissents do push the length of majority opinions up at least somewhat. The correlation between special concurrences and majority opinions, on the other hand, is only 0.1261 – a very low correlation, indicating that the presence of a special concurrence has relatively little tendency to make majority opinions longer.
Join us back here on New Year’s Day as we turn our attention to the Court’s criminal docket. Happy Holidays!