When we left off our study, one-third of the Supreme Court’s civil cases were drawing at least one amicus brief.  In 2005, 27.08% of civil cases did.  That figure rose to 34.69% in 2006 before falling by nearly half but rose back to 31.58% in 2011 and 32.35% in 2013.  In 2017, 61.54% of the Court’s civil cases had at least one amicus brief.  In 2018, 27.27% did.  In 2019, 41.18% did, and the share was 37.5% in 2020.

Appellants averaged one-third of an amicus brief per case in 2005.  After a one-year spike in 2006, that fell to 0.1463 in 2007 before rising to 0.3636 in 2010.  By 2012, appellants were averaging 0.425 briefs per case.  After a small dip, that rose to 0.4545 in 2015, 0.6154 in 2017 and 0.7647 in 2019.

As usual, there were fewer amicus briefs filed in support of appellees.  In 2005, appellees averaged 0.1875 briefs per case.  That increased to 0.3939 by 2010 and stayed around that level for three more years before falling back in the three years following.  In 2017, 0.3846 briefs per appellee were filed.  After a one-year dip, that rose to nearly the same level – 0.3824 briefs per case in 2019, before settling to 0.25 in 2020.

Join us tomorrow as we review the data for the same years in criminal cases.

Image courtesy of Flickr by Curtis Abert (no changes).