S.D. Codified Laws § 3-18-4
When a governmental agency declines to grant formal recognition or when a question concerning the designation of a representation unit is raised by the governmental agency, labor or employee organization, or employees, the Department of Labor and Regulation or any person designated by it shall, at the request of any of the parties, investigate such question and, after a hearing if requested by any party, rule on the definition of the appropriate representation unit. The department shall certify to the parties in writing the proper definition of the unit. In defining the unit, the department shall take into consideration, along with other relevant factors, the principles of efficient administration of government, the principles and the coverage of uniform comprehensive position classification and compensation plans in the governmental agency, the history and extent of organization, occupational classification, administrative and supervisory levels of authority, geographical location, and the recommendations of the parties.
SDCL 3-18-4