Wis. Admin. Code Employment Relations Commission ERC 30.07
After a petition or stipulation has been filed, unless the parties have agreed in writing on another procedure, the commission shall assign a commission-employed investigator who shall, after conferring with the parties, set a date, time and place for the conduct of an informal investigation or for the conduct of a formal hearing with respect to the petition or stipulation. If, during any mediation by a commission mediator, the parties have exchanged and submitted to the mediator their total final offers, as well as a stipulation on matters agreed upon, the parties may waive the informal investigation or formal hearing described in s. ERC 30.08. A waiver shall be written and may accompany the petition or stipulation for initiation of interest arbitration or be filed separately later.
Wis. Admin. Code Employment Relations Commission ERC 30.07