The burden of going forward refers to the party with the obligation to present evidence first on a matter in dispute. The phrase “burden of proof,” or “burden of persuasion,” refers to the ultimate obligation to demonstrate sufficient evidence borne by one of the parties. Burdens may apply to particular issues as well as to the case as a whole. In disputes involving contract interpretation the burden typically rests with the union as the grieving party. In contrast, in disciplinary matters the burdens of going forward and proof typically are assigned to the employer as the party altering the status quo. The allocation of burdens also applies to particular issues such as arbitrability and affirmative defenses (for example, the burden to demonstrate untimely grievances, negotiation waivers, disparate treatment, mitigation of damages, etc.).