An Article addressing the varying admissibility standards in federal court for expert evidence at the class certification stage, the common types of expert evidence presented at the class certification stage, the standard for making Daubert motions, a discussion of the seminal US Supreme Court decisions in Wal-Mart Stores, Inc. v. Dukes and Comcast Corp. v. Behrend and their impact on the lower courts’ consideration of expert evidence at the class certification stage, and key tips and takeaways for counsel navigating putative class actions.