Article XX, Complaint, Grievance, and Arbitration procedure: This article describes the grievance procedure, a formal mechanism for resolution of disagreements between a House Officer and the Employer or between the Association and the Employer involving interpretation or application of the terms of the Agreement. The Employer and the Association may mutually agree to add a process for dispute mediation prior to arbitration. In this event, the parties will agree on a list of mediators to use and will share the costs of mediation equally.