A group of Florida landowners sued Raytheon Company, accusing it of contaminating their groundwater by improperly disposing of hazardous waste. The plaintiffs put up an expert who testified that he could construct a statistical model that would demonstrate liability and damages on a classwide basis.  Raytheon put up its own experts, who argued that plaintiffs’ method of defining the affected area was not consistent with "applicable professional standards," and that their expert’s statistical method was unsound as well.  

The district court threw up its hands.  Declaring 

[i]t is not necessary at this stage of the litigation to declare a proverbial winner in the parties’ war of the battling experts or dueling statistics and chemical concentrations

it certified the proposed class, and left the Daubert question for trial.

Raytheon appealed.  The Eleventh Circuit–in an opinion not designated for publication–reversed the trial court. Its primary reason to do so was 

Here, in its Rule 23 analysis, we find that the district court erred as a matter of law by not sufficiently evaluating and weighing conflicting expert testimony on class certification. It was error for the district court to decline to declare a proverbial, yet tentative winner. The Plaintiffs are required to prove, at the class certification stage, more than just a prima facie case, i.e., more than just a pretty good case.

Here the district court refused to conduct a Daubert-like critique of the proffered experts’s qualifications. This was error. As we have noted, a district court must make the necessary factual and legal inquiries and decide all relevant contested issues prior to certification. The district court has not determined facts, from the often conflicting evidence, sufficient to determine whether class certification is or is not appropriate. The court erred in granting class certification prematurely. Tough questions must be faced and squarely decided. Such tough questions were side-stepped by the district court in this case. That was error.

The Eleventh Circuit remanded the case for further proceedings, and declined to express an opinion about whether certification would ultimately prove appropriate.  

It’s interesting that the Eleventh Circuit has chosen not to publish the opinion.  It relied heavily on the Seventh Circuit’s opinion in American Honda Inc. v. Allen, and this ruling aligns it with the Second and Third Circuits as well. And this opinion would put the Eleventh Circuit opposite the Ninth’s opinion in Dukes v. Wal-Mart.  Since the Supreme Court is hearing that case next week, it’s entirely possibly that, rather than picking a winner itself, the Eleventh Circuit decided to hedge its bets.