Which Side Tends To File The Most Amicus Briefs In Civil Cases (Part 1)?

For the past several weeks, we've been reviewing the Supreme Court tenure of soon-to-retire Justice Kathryn Werdegar. This week, we begin a new topic. Several weeks ago, we tracked the average number of amicus briefs filed, case by case, from year to year. But with the expansion of our data library, we can now track the average number of amicus briefs filed according to which side the amicus supported. So who averages more briefs, petitioners or respondents? We begin today by reviewing the yearly data for civil cases between 1994 and 2005.

We report the data in Table 207 below, divided up by average briefs supporting the petitioners, the respondents, and briefs which either took no side, or which couldn't be definitively assigned based on the online docket. We see that three quarters of the time between 1994 and 2005, petitioners tended to average more amicus support than respondents did. The yearly averages were surprisingly stable on both sides of the case. In 1994, petitioners in civil cases averaged 1.61 amicus briefs. The following year, the average was 1.56. In 1996, the average was 1.23. For the same period, the averages for respondents were 0.98, 1.37 and 1.17, respectively.

In 1997, petitioners averaged 2.1 additional briefs to 1.24 for respondents. The following year, petitioners' briefs had fallen sharply to 1.17, while...