The last few weeks have been exceptionally busy for appellate decisions involving class actions. In addition to Judge Easterbrook’s In re Aqua Dots opinion, the Sixth Circuit’s Pipefitters opinion, the Second Circuit’s Literary Works opinion, and the Ninth Circuit’s reversal of the Bluetooth settlement, the Third Circuit has offered up a pair of opinions involving predominance and common evidence. In one, Behrend v. Comcast Corp., a panel appeared to limit the reach of In re Hydrogen Peroxide on expert evidence, affirming certification of an antitrust case again the cable provider in part because it held that a Daubert inquiry is not necessary at class certification. In the other, Gates v. Rohm & Haas Co., a different panel affirmed the denial of certification of an environmental class action. In doing so, it appeared to follow Hydrogen Peroxide in requiring a "rigorous analysis" of expert proof, even if the parties themselves had stipulated no Daubert hearing would be necessary.

In general, Gates is an extremely useful opinion for defendants. Leaving aside its implicit analysis of the Daubert issue (which is likely to be hotly contested for some time to come), the Third Circuit made a number of other statements explaining just how difficult it can be to demonstrate either cohesiveness (for a Rule 23(b)(2) class) or predominance (for a Rule 23(b)(3) class).

I blogged about this case last year when the trial court denied certification. So, since it remains applicable, I’ll repeat the factual summary from there.

Gates is an environmental case, in which the plaintiffs sued Rohm & Haas for polluting the water and air around Ringwood, Illinois with chemicals including vinylidene chloride, a known carcinogen. The plaintiffs sued for violations of CERCLA and state law, and sought damages for medical monitoring and damage to property. The proposed class action – like many environmental class actions – would turn on questions of causation, which can pose a number of thorny individualized issues in toxic torts. So, in addition to seeking damages, the plaintiffs sought an injunction compelling Rohm & Haas to set up a medical monitoring regime.

The district court refused to certify a class, finding that the Rule 23(b)(2) class lacked "cohesiveness" and the 23(b)(3) class lacked predominance. The plaintiffs appealed.  The Third Circuit affirmed. Among its holdings:

The "cohesiveness" requirement for Rule 23(b)(2) is more stringent than the predominance requirement for Rule 23(b)(3).

As all class members will be bound by a single judgment, members of a proposed Rule 23(b)(2) injunctive or declaratory class must have strong commonality of interests.

The Third Circuit also noted that

Commentators have noted that certification requirements under Rule 23(b)(2) are more stringent than under (b)(3).

The plaintiffs could not rely on proof of a composite, "average" class member to establish factual predominance.

Plaintiffs cannot substitute evidence of exposure of actual class members with evidence of hypothetical, composite persons in order to gain class certification. … Averages or community-wide estimations would not be probative of any individual’s claim because any one class member may have an exposure level well above or below the average.

Nor could plaintiffs use regulatory standards as shortcuts for common proof.

Although the positions of regulatory policymakers are relevant, their risk assessments are not necessarily conclusive in determining what risk exposure presents to specified individuals. … Thus, plaintiffs could not carry their burden of proof for a class of specific persons simply by citing regulatory standards for the population as a whole.

In short, the Third Circuit came out definitively against using some of the various shortcuts plaintiffs have employed to convince courts to certify a class despite the lack of actual common proof. As both a taxonomy of these shortcuts, and an explanation of why they don’t work, this is a good opinion for class-action defense lawyers to keep in their toolkit.