The district court for the Northern District of Illinois recently denied plaintiff’s motion for class certification in Langendorf v. Skinnygirl Cocktails (2014 WL 5487670), calling attention to the ascertainability requirement that plaintiffs must meet in order to certify a class. My colleague Isabella Lacayo has previously written on ascertainability, explaining that while it is not a requirement that’s explicitly discussed in Rule 23, courts have implicitly required that plaintiffs seeking to certify a class must be able to identify a precisely-defined class through the use of objective criteria. While this may sound relatively straightforward, that’s not always the case.

Langendorf sued Skinnygirl Cocktails on behalf of a putative Illinois class, alleging that despite its “all natural” label, Skinnygirl Margarita, a pre-mixed alcoholic beverage, contains sodium benzoate–a “non-natural” preservative. Langendorf alleges that the “all natural” label is false and misleading, and sued the makers and promoters of the Skinnygirl Margarita under the Illinois consumer fraud statute, under Illinois warranty statutes, and under various common law theories.

The district court denied the plaintiff’s motion for class certification on several grounds, but its analysis of the ascertainability requirement is particularly notable. The court explained that under Seventh Circuit law, a plaintiff seeking to certify a Rule 23 class must show that the proposed class is “sufficiently definite that its members are ascertainable” before showing that the explicit requirements of Rule 23 are satisfied. Importantly, the court noted, under Comcast, the plaintiff must “affirmatively demonstrate” compliance with Rule 23 through “evidentiary proof.” Mere allegations, therefore, are insufficient to support class certification.

The plaintiff sought to certify the following class: “Any and all persons who purchased ‘Skinnygirl’ Margarita spirits in Illinois from March 1, 2009 until the date notice is disseminated. . .” The court explained that while it is not necessary at the class certification stage to know the identities of all class members, there must be “some objective criteria by which the identities can be determined.” Additionally, the plaintiff must offer “a method for ascertaining class members with some evidentiary support that the method will be successful” (citing Carrera v. Bayer Corp., 727 F.3d 300, 306 (3d Cir. 2013)). More on Carrera shortly.

The court found that while Langendorf satisfied the objective criteria requirement (purchasers of the relevant product after a certain date and lack of association with the defendants or the court), she failed to offer a method by which the court could find out who the purchasers were. Plaintiff argued that class membership can be verified by the dates of purchase, the locations of retail establishments, the quantity and frequency of purchases, and the cost of purchase. But the court noted that the plaintiff provided no evidence that “any records exist that show who purchased the offending product, when, or where.” Defendants pointed out that they never sold product directly to consumers, so they also lack the relevant records needed to prove the identities of class members. The court’s opinion emphasized that the burden is on the plaintiff to demonstrate that the class can be identified.

Carrera, the Third Circuit case relied on by the district court to note the expectation that plaintiffs provide evidentiary support for ascertainability, is a somewhat controversial case. As the Langendorf court itself noted, the court’s decision in Carrera “could be read to impose too high a burden on plaintiffs in consumer class actions,” citing a dissenting opinion from Carrera’s denial of rehearing en banc (2014 WL 3887938). The district court acknowledged that while Carrera is not binding authority in the Seventh Circuit, its general premise is nevertheless persuasive.

In Carrera, there was no dispute that the defendant did not sell the product at issue to consumers. It was also undisputed that prospective class members were unlikely to have documentary proof of purchase, since few people keep receipts for low cost items or drugstore purchases. While the Carrera court determined that class members could theoretically be ascertained through loyalty and reward card purchases, online sales, and affidavits, the court still found that the plaintiffs’ methods for determining the identity of its class members were insufficient. The dissent from denial of rehearing en banc raises the following questions: Does the ascertainability standard Carrera sets for plaintiffs “threate[n] the viability of the low-value consumer class action that necessitated Rule 23 in the first instance”? What is an “administratively feasible method” to make class-wide determinations about ascertainability?

As courts in different jurisdictions continue to explore the question of what is a sufficient ascertainability showing, what’s clear is that defendants should continue to keep potential ascertainability arguments on their radar. While they may not always win the day, the Langendorf decision and others like it show that courts are receptive to them and will often hold plaintiffs to the evidentiary standards set forth in Comcast.