Bellwether trials are a small group of lawsuits, chosen from a larger group of similar cases, to be tried first. The outcomes of bellwether trials serve as a sort of litmus test for how future litigation might turn out.
The term “bellwether” derives from the long ago practice of placing a bell around the neck of the lead sheep in a flock so that the flock’s movement could be determined from a distance. From this the word bellwether (meaning one that leads or indicates trends) came into usage.
Bellwether trials are associated with multidistrict litigation (MDL), a legal mechanism that consolidates a group of related lawsuits filed in different districts into a single district to make it easier to coordinate pretrial discovery (the process whereby plaintiff’s lawyers and defense lawyers gather and share evidence).
MDLs can contain thousands of separate lawsuits, which makes timely resolution of all cases a challenge. To accelerate case outcomes a handful of bellwether trials are selected. The results of these cases, which are chosen on the basis that they are representative of the MDL class as a whole, aren’t binding on the other cases, but like the lead sheep in a flock they can help to show the group’s direction.
During bellwether trials each side gets to test the strength of their evidence and see how it sways the court. If the court finds in favor of the plaintiff in the majority of bellwether cases—and especially if the compensation awarded to plaintiffs is high—the defendant may be more inclined to settle the remaining cases. But if the defendant prevails in bellwether trials, it would likely encourage the defendant to forego settlement and try its luck in the courtroom.