Law360, New York (December 18, 2013, 8:31 PM EST) -- Whether an arbitration agreement authorizes classwide arbitration can have "momentous consequences" — for instance, making the difference between arbitrating "one claim or 1,000 in a single proceeding." Reed Elsevier v. Crockett, 734 F.3d 594 (6th Cir. 2013). Equally consequential is who — courts or arbitrators — interprets the parties' arbitration agreement[1] to determine if it allows classwide arbitration. Arbitrators' rulings are given great deference under the Federal Arbitration Act ("FAA") and are upheld if they "even arguably" construe the arbitration agreement, while a district court addressing that question must apply established canons of contract construction, and its decision is subject to de novo appellate review....