We love the word "bellwether" -- a noun meaning "a male sheep that leads the flock; it normally wears a bell."
We don't love bellwether trials, but we'll take 'em, because they're the best an MDL judge can offer.
On the one hand, a bellwether trial in an MDL (or statewide coordinated) proceeding isn't very informative. Trying one or two cases out of a collection of hundreds, or thousands, certainly doesn't give any statistical information about the value of the cases. The one or two cases are not a statistically significant cross-section of the mass of litigation.
Moreover, the many pending cases (at least in the product liability field) probably differ from each other in ways that make their settlement values vary. Trying one case may not say much about the value of the next. And the performances of witnesses, trial counsel, and judges, and the make-up of juries, will vary across trials, too, so a few early trial results aren't particularly meaningful.
A few early trial results can, however, have unfortunate effects. They can, for example, decrease the chance of a prompt global resolution of a mass tort. A big plaintiff's verdict may unreasonably raise the expectations of the plaintiffs' bar; a resounding defense win may make the defense too stubborn. And, ultimately, global settlements turn on what the parties are willing to pay (and accept) to resolve the cases, which may have little to do with the results at trial.
On the other hand, what's the alternative to holding bellwether trials? Discovering up 5000 cases simultaneously without trying any? That's a disaster. Discovering up 5000 cases and setting them all for trial? That's silly (and impossible). Cobbling together classwide trials in situations that don't merit them? That's both bad law and bad policy. Trying to devise a "trial by statistics" that doesn't suffer from the due process and other concerns discussed by the Fifth Circuit in Cimino v. Raymark, 151 F.3d 297 (5th Cir. 1998), and elsewhere? That's a procedural morass.
And bellwether trials do provide some information. They force plaintiffs' counsel to do the work needed to prepare their standard trial package, and the early trials give some sense of how sound that package is. The bellwether trials force the court to resolve legal questions that arise only as a trial actually approaches and witnesses begin to take the stand. And the bellwether trials test the expert witnesses and give both parties a sense of how much it costs to try a case.
Finally, for a judge who's considering certifying a class, trying one (or several) bellwether trials might be very informative. There's nothing like a real trial to help assess whether plaintiff's proposed class trial plan is workable, whether claims and defenses are in fact individualized, and to shed light on other class certification issues. In some categories of cases, one could reasonably argue that judges should be required to try a case or two before deciding to certify a class.
Bellwether trials are not the perfect way to resolve mass torts, but they're basically all that an MDL judge has to offer. Until someone suggests a viable alternative, we'll settle for the best that's available.