The U.S. Supreme Court on Monday said a lower federal appeals court was wrong to count a deceased judge in its majority decision in a major case involving whether employers can use salary history as a reason to pay a woman less than a man for the same work.

The justices said in an unsigned opinion in Yovino v. Rizo, that Judge Stephen Reinhardt was no longer a judge when the U.S. Court of Appeals for the Ninth Circuit filed its en banc opinion. The court vacated a ruling that forbade employers from using prior salary history in justifying wage differences between male and female employees. The justices did not examine the merits of the dispute.