Once on the Supreme Court the Justices have a few essential obligations. Add to this life-tenure and lots of free time while the Court is in recess and the job sounds pretty enviable. The Justices still must hear oral arguments, meet and vote to decide cases, and grant new cases for the Court to hear each Term. In terms of output though, their main obligatory contribution is writing majority opinions. The Justices are also free to write separate opinions and as is evident with Justice Thomas last Term, this may take up a large portion of a Justices’ energies. Still, separate opinions are optional in a way that majority opinions are not.

One way to judge the Supreme Court Justices then is through their efficiency in this obligatory output. The Justices are assigned a certain number of opinions every term. Depending on a multiplicity of factors, there is a range in the amount of time between when a case is orally argued and when a decision is rendered and released. These factors include the importance of the decision, the relative consensus of the Justices and the time it takes a Justice to pen an opinion that garners the support of a majority of the Justices. One of the most important factors has to do with how many opinions a Justice authors in a Term. These factors all play into a Justice’s expediency in moving from oral argument to written opinion.
In the 2015 Term there was a large range of 190 days in the time it took the Justices to go from oral argument to releasing opinions. At the high end, the opinion in Ocasio was released 209 days after oral arguments while at the low end the opinion in Welch was released 19 days after oral argument. The unique nature of losing a Justice mid-Term may have also led to increased time between oral arguments and opinions, especially when the Justices could not aggregate a majority of votes in a given case.

Bearing in mind that there are factors outside of the Justices control that lead to the lag-time between oral arguments and the release of opinions, this post gives a glimpse into the Justices’ efficiencies in this territory across the Roberts Courts years to the present.

When we look at a graph of the average time each Justice took between oral arguments and their written opinion for this time period the result is the jumble that composes the figure below.

Although bits of information are visible in this graph, like Justice Kennedy’s increase in average time (in days) to opinion and subsequent decrease in time, the Justices tend to cluster fairly closely. A snapshot in time gives more of a sense of their variation. Take the Term that just completed for instance:

If we discount Justice Scalia’s average time between oral argument and his two written opinions the range between Justice Kagan’s average at the high end and Justice Ginsburg’s average at the low end is 40.2 days.

We can also look at the Justices average times between 2005 and 2015.

Since Justice O’Connor only wrote three opinions during this period, the real range of significance is between Justice Ginsburg’s average of 76.7 days and Justice Kennedy’s of 114.8 days (for a range of 38.1 days). These numbers, however only tell part of the story. The number of opinions the Justices write each Term, their workloads, may enhance or slow down the time it takes them to get through the individual opinions. Including the 62 signed opinions from this past Term, the Justices authored 833 signed majority opinions between the 2005 and 2015 Terms. Across these Terms Justice Scalia authored the most with 106 opinions followed by Justice Kennedy with 103 opinions. Of the Justices on the Court across the entire period Justice Ginsburg authored the fewest majority opinions with 88 (Justice Alito authored 81 but his role on the Court did not start until the middle of the 2005 Term).

After calculating the average number of days between oral argument and written majority opinion and total opinions written in a Term, there is sufficient data for a rough sense of the Justices relative efficiencies. I calculated these efficiency scores for a Justice on a term-by-term basis based on the average time between oral argument and written opinion divided by the number of majority opinions a Justice authored. The graph for this data across the cumulative Roberts Court years is not very telling as the Justices cluster relatively closely together. Instead by first looking at the 2015 Term we can begin to get a sense of the Justices recent efficiency levels.

If we similarly overlook the mark for Justice Scalia, we see that Justice Ginsburg was the most efficient Justice with a score of 9.3 (an average of one opinion released for every 9.3 days between oral argument and opinion) and the least efficient Justice was Justice Alito with a score of 15.7.

Now, of course, one Term gives only minimal insight into a Justice’s efficiency while on the Court. With more observations in hand, we can discern a Justice’s ability to turn around written opinions with much more confidence in the measure. Perhaps surprisingly, the figure for Justice efficiency across the 2005 through 2015 Terms is not markedly different than the 2015 Figure.

If we discount Justice O’Connor’s score based on her three total opinions, then the spectrum of Justice efficiency is similarly bracketed by Justices Ginsburg and Alito. Justice Kennedy who wrote the most 5-4 decisions  (that often are released at the end of the Term) over this period finished more efficient than both Justices Alito and Kagan.

To reiterate, there are many more factors that play into a Justice’s efficiency than just the time between oral argument and opinion and the number of majority opinions they author. This measure though provides novel information about the Justices’ output.
These findings may provide a counterpoint to the recent uproar about Justice Ginsburg’s comments surrounding Presidential candidate Donald Trump and the consequent rhetoric about how such political comments should be off-bounds for the Justices (including this post from Josh Blackmun). While in some sense she stepped outside of her role as Justice by making these comments, at least by these findings, as a Justice she is doing her job more efficiently than any other Justice on the Roberts Court.

On Twitter: @AdamSFeldman
Data Collection supplemented with information from the Supreme Court Database.