Michigan Compiled Law Section 211.34 subsection 3 mandates the function of the County Equalization function.

What does M.C.L. 211.34(3) say?

The county board of commissioners of a county shall establish and maintain a department to survey assessments and assist the board of commissioners in the matter of equalization of assessments, and may employ in that department technical and clerical personnel which in its judgment are considered necessary.  The personnel of the department shall be under the direct supervision and control of a director of the tax or equalization department who may designate an employee of the department as his or her deputy.  The director of the county tax or equalization department shall be appointed by the county board of commissioners. The county board of commissioners, through the department, may furnish assistance to local assessing officers in the performance of duties imposed upon those officers by this act, including the development and maintenance of accurate property descriptions, the discovery, listing, and valuation of properties for tax purposes, and the development and use of uniform valuation standards and techniques for the assessment of property.