On February 29, the Supreme Court denied certiorari review in
Mullins v. Direct Digital, LLC, No. 15-1776. The
Mullins decision, which arose out of the Seventh Circuit,
created a circuit split with the Eleventh and Third circuits with
respect to the implicit "ascertainability" requirement
that those two circuits had found precluded class
certification. In Mullins, the Seventh Circuit held
that a class plaintiff is not required to demonstrate the
"administrative feasibility" of ascertaining a
class. Rather, a plaintiff must only demonstrate that the
class definition is "defined clearly and based on objective
criteria."
The "implicit" element of ascertainability has
recently gained traction at the district court level as a major
obstacle to class certification in certain cases. The
requirement is generally viewed as mandating that class membership
be, in practice, objectively ascertainable and not require the
extensive use of "mini-trials" to
