Just a decade ago, it was still an open question whether parties could challenge the admissibility of expert testimony in class certification proceedings. The United States Supreme Court recognized the issue in Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338 (2011), and suggested that experts should be scrutinized as usual, noting that “The District Court concluded that Daubert did not apply to expert testimony at the certification stage of class-action proceedings. We doubt that this is so . . .” Since then, multiple circuits have taken that hint and held that a court must conduct a full Rule 702 analysis before deciding whether to certify a class. The Fifth Circuit, in Prantil v. Arkema Incorporated, 986 F.3d 570 (5th Cir. 2021), became the fourth federal court of appeal to adopt this rule expressly. As the district court’s recent decision on remand in Prantil demonstrates, a full Rule 702 analysis can make the difference between certifying or rejecting a class.