This Bloomberg article discusses how Justice's personalities come through in Opinions Related to Orders (ORTOs):
The U.S. Supreme Court’s “opinions related to orders” get less attention than their merits opinions, but they give courtwatchers clues about the justices who write them.Interestingly, although Thomas doesn't speak at oral arguments, he comes in second with 24 ORTOs.
Merits opinions set a binding rule for the entire country to follow. Opinions related to orders—ORTOs—are often the thoughts of one justice on a case the court has decided not to take up.
The justices vary quite a bit in how often they write opinions related to orders, Bloomberg Law analysis shows. Since October 2011, Justice Sonia Sotomayor has written 31 opinions related to orders. Justice Anthony M. Kennedy has written none.
“I think it isn’t surprising that there’s some variation between the Justices,” Daniel Epps, a former clerk for Kennedy, told Bloomberg Law. “But I think it is a bit surprising just how much variance there is.”