One of the central institutional features of the United States courts of appeals is the use of judicial panels to decide cases. Rather than having a single appellate judge decide each appeal, or even having a group of appellate judges deciding in isolation and tallying their votes, the appeals process is specifically structured to promote a collaborative form of decision making. Three appellate judges are assigned to decide a case together, and they typically share their background research, sit together as a panel to hear oral arguments, meet to discuss their views, and issue a single opinion resolving the appeal. Of course, not all cases are typical, and judges sometimes dissent or concur separately. These occurrences are relatively infrequent, however, and cases involving separate opinions are viewed as deviations from the usual model of appellate decision making. Thus, as D.C. Circuit Judge Harry Edwards put it, "judging on the appellate bench is a group process."

As a matter of institutional design, why are federal appellate courts structured in this way? Certainly it is not for the sake of efficiency, as the same number of judges sitting alone could decide appeals more quickly than when sitting with two of their colleagues. Most explanations focus on the quality of decision making. Kornhauser and Sager, for example, assert that increasing the number of judges making a decision will increase the probability that a court will reach a correct decision. So long as each judge is more likely than not to decide correctly, a correct outcome is more likely whenever a group of judges decides by majority vote. Others have suggested that this error-reducing effect results from the exchange of ideas and information that occurs during the process of deliberation. For example, Judge Edwards describes the interactions among judges on an appellate panel as "a process of dialogue, persuasion, and revision" that enables them to "find common ground and reach better decisions."