As one would expect, due to the numerosity of the individual cases within an MDL (multidistrict litigation) pool, it is impractical – and indeed, impossible – to try all MDL cases immediately upon completion of discovery and pre-trial proceedings. 

     To address this issue, bellwether trials are used in MDL proceedings. In a bellwether trial procedure, a sample of randomly selected cases serve as “test” cases in order to educate the court and the parties about the strengths and weaknesses of the remaining cases within the MDL. 

     The term “bellwether” is derived from the ancient practice of placing a bell around a wether (a male sheep) selected to lead his flock so that the flock could be tracked and monitored.

     “The ultimate success of the wether selected to wear the bell was determined by whether the flock had confidence that the wether would not lead them astray, and so it is in the mass tort context.” In re Chevron U.S.A., Inc., 109 F.3d 1016, 1019 (5th Cir. 1997). 

     Thus, in order to serve their primary purpose, the bellwether cases selected must – in some aspect – be representative of all the cases in the MDL pool. 

     As one Court put it: “A bellwether trial designed to achieve its value ascertainment function for settlement purposes or to answer troubling causation or liability issues common to the universe of claimants has as a core element representativeness—that is, the sample must be a randomly selected one of sufficient size so as to achieve statistical significance to the desired level of confidence in the result obtained.” Id.

     While bellwether trials assist in predicting possible outcomes in future litigation, the verdict issued in a bellwether trial is not binding on the remaining cases in the MDL pool nor does it guarantee the same verdict across the MDL.

      The designated trial court will promptly create a discovery schedule and select test cases — called “bellwether trials” — to encourage settlement actively.