Commonality is rarely the subject of much discussion in class certification. The plaintiff often treats it as a perfunctory hurdle, subsumed into the more difficult questions of predominance (under Rule 23(b)(3)) or cohesiveness (under Rule 23(b)(2)).  But, much like numerosity, commonality is a requirement that may reward careful scrutiny when a defendant opposes class certification.

In Gaston v. Exelon Corp., 247 F.R.D. 75 (E.D. Pa. 2007), a group of African-American employees sued their employer for engaging in various policies (including its promotion and compensation decisions) that they claimed violated Title VII. They sought to represent a class of employees

who have been or may be subjected to Exelon’s challenged policies and practices that deny Black exempt employees equal opportunity …

Exelon filed a motion to strike class allegations, which the court granted in part, ruling that no 23(b)(2) class was possible. When the plaintiffs later moved to certify a Rule 23(b)(3) class, the court actually found a number of problems with plaintiffs’ class proposal. The class definition was not ascertainable. The named plaintiffs were subject to unique defenses, making them inadequate and atypical representatives. But the fundamental problem the court found was that the proposed common issues were not common.

In fact, the court took a Goldilocks-like approach to commonality (that is, if Goldilocks hadn’t liked the baby bear’s stuff either). It found that the proposed common issues were either too broad, too narrow or just plain irrelevant. What do I mean by too broad? As the court put it:

[P]laintiffs’ first proposed question is “whether PECO’s performance evaluation policy or practices negatively impact Class members.” Id. Were a question of this sort suitable to demonstrate commonality, that requirement would become a puff of smoke. Plaintiffs could simply propose the ques- tion “has employer discriminated against class mem- bers” and always meet the commonality requirement. Obviously, something more is necessary.

As for too narrow:

Other supposedly common questions that plaintiffs identify apply only to a small fraction of the proposed class. The question “whether Class members are less likely to be promoted into intermediate- or high-level salary grades than are otherwise-similar White employees,” for example, only applies to class members who were eligible for a promotion into those grades.

And finally, the court found that the remaining common questions had no bearing on the case itself.

Other questions, such as “whether Class members are less likely to be in high-level salary grades,” are simply irrelevant to a Title VII suit. As we discussed above, it is not sufficient for plaintiffs merely to identify a disparity in the representation of black employees in higher salary grades. They must also identify a pattern or practice of employment decisions during the class period that has resulted in this disparity.

What does this analysis mean for defendants? Despite the traditional view that commonality is a low hurdle for the plaintiff to clear, it is still worth challenging when the only common questions have nothing to do with the heart of the case.