The likelihood that a provision for final-offer arbitration in the event of impasse will actually result in arbitration is slim. However, as a precaution, you and your counterpart should agree on an arbitrator before you start negotiating. It’s easier to choose an arbitrator when both sides view arbitration as an unlikely event when arbitration is imminent and feelings are running high. You need not engage the arbitrator at this time since you probably won’t need her services.