For the past few weeks, we’ve been looking at how often each member of the Court since 1990 voted with the majority in divided decisions on both the civil and criminal side, looking both for how closely aligned each Justice was with the majority of the Court, and perhaps a rough indicator of each Justice’s influence among his or her colleagues.  This time, we begin working on a slightly different voting indicator – how often did each Justice agree with each of his or her individual colleagues on the Court?  Today, we’ll begin a three-week trip through the Court’s recent history on the civil side, then we’ll look at the criminal side.

But first, a few ground rules.  In order to smooth out what are really random variations from year to year, we’ll group the twenty-nine-year period by looking at six years at a time – thus better seeing real relationships and trends.  Second, just as with the last series of posts, “agreement” means complete agreement – a Justice who votes to affirm and another who votes to affirm in part and reverse in part are not counted as agreeing in this data.  Third, because the Court’s unanimity rate is typically so high, we’re addressing non-unanimous decisions only (otherwise, most of these combinations would be clustered relatively high on the bar charts).  Fourth, in the data below, we address every possible combination of Justices who voted in even a single case during these years, taking fifteen combinations at a time.

We report our first set of combinations in Table 1003 below.  Justices McMorrow and Miller had the highest agreement rate during these years – 90.48% of non-unanimous civil decisions.  Five combinations were over eighty percent – Justices Clark and Calvo, 89.47%, Justices Clark and Cunningham, 87.18%, Justices Clark and Bilandic, 75.71% and Justices Clark and Freeman, 85.37%.  Three more combinations of Justices were in the seventy percent range – Justices Clark and Moran, 75.86%, Justices Clark and Ward, 75%, and Justices Nickels and McMorrow, 73.77%.  Among the lowest agreement rates in this first grouping were three combinations in the fifty percent rage – Justices Clark and Miller, 54.24%, Justices McMorrow and Heiple, 50.79%, and Justices Clark and Stamos, 50%.  Justices McMorrow and Harrison agreed in only 40.68% of divided civil cases during these years.  Finally, Justice Clark’s agreement rates were in the thirties with two of his colleagues – Justice Ryan (37.5%) and Justice Heiple (33.33%).

In Table 1004, we report the data for the next fifteen combinations of Justices.  The data for these Justices varies significantly less than the first group, mostly because almost no one in this group reached as high a number as the first: in our first group, five combinations of Justices had agreement rates over 80%, while here, only one – Justices Freeman and Calvo, four agrees in four cases, did.  Five combinations had agreement rates in the seventies – Justices Miller and Stamos (73.33%), Justices Miller and Ryan (75%), Justices Miller and Moran (77.97%), Justices Miller and Cunningham (71.79%) and Justices Freeman and Cunningham (78.38%).  Another five combinations were in the sixties – Justices McMorrow and Bilandic (61.29%), Justices Miller and Freeman (65.09%), Justices Miller and Heiple (63.89%), Justices Miller and Nickels (62.12%) and Justices Miller and Bilandic (61.54%).  Meanwhile, one combination had an agreement rate in the forties – Justices Miller and Harrison (46.77%), and one was in the thirties – Justices Miller and Calvo (35%).

The spread among the next fifteen combinations of Justices was similar.  Only one combination had an agreement rate of 80% – Justices Stamos and Moran.  Three more were in the seventies – Justices Freeman and Moran (75.61%), Justices Freeman and Nickels (71.21%) and Justices Heiple and Nickels (70.15%).  Two combinations of Justices were in the forties – Justices Heiple and Cunningham (46.15%) and Heiple and Harrison (49.21%).  Justices Ryan and Moran had an agreement rate of 31.25%.

In Table 1006, we report the remaining agreement rates for the period of 1990 to 1995.  Justice Calvo’s agreement rate with Justices Bilandic and Cunningham was 100%.  The agreement rate between Justices Moran and Cunningham was 94.87%.  Four combinations – Justices Moran and Bilandic (72.73%), Justices Moran and Ward (75%), Justices Calvo and Ward (75%) and Justices Cunningham and Bilandic (70.97%), had agreement rates in the seventies.  At the bottom of this set was Justices Ryan and Calvo, whose agreement rate was 31.25%.

Join us back here next time as we explore the data for the years 1996 through 2001.

Image courtesy of Flickr by Gabe Popa (no changes).