First, the decision to certify a class calls for findings by the court, not merely a “threshold showing” by a party, that each requirement of Rule 23 is met.... Second, the court must resolve all factual or legal disputes relevant to class certification, even if they overlap with the merits — including disputes touching on elements of the cause of action. Third, the court’s obligation to consider all relevant evidence and arguments extends to expert testimony, whether offered by a party seeking class certification or by a party opposing it.
Slip op. at 5. Class certification was reversed and remanded.