Michigan Compiled Law 722.26a Joint custody.
Sec. 6a.(1) In custody disputes between parents, the parents shall be advised of joint custody. At the request of either parent, the court shall consider an award of joint custody, and shall state on the record the reasons for granting or denying a request. In other cases joint custody may be considered by the court. The court shall determine whether joint custody is in the best interest of the child by considering the following factors:
(a) The factors enumerated in section 3.
(b) Whether the parents will be able to cooperate and generally agree concerning important decisions affecting the welfare of the child.
(2) If the parents agree on joint custody, the court shall award joint custody unless the court determines on the record, based upon clear and convincing evidence, that joint custody is not in the best interests of the child.
(3) If the court awards joint custody, the court may include in its award a statement regarding when the child shall reside with each parent, or may provide that physical custody be shared by the parents in a manner to assure the child continuing contact with both parents.
(4) During the time a child resides with a parent, that parent shall decide all routine matters concerning the child.
(5) If there is a dispute regarding residency, the court shall state the basis for a residency award on the record or in writing.
(6) Joint custody shall not eliminate the responsibility for child support. Each parent shall be responsible for child support based on the needs of the child and the actual resources of each parent. If a parent would otherwise be unable to maintain adequate housing for the child and the other parent has sufficient resources, the court may order modified support payments for a portion of housing expenses even during a period when the child is not residing in the home of the parent receiving support. An order of joint custody, in and of itself, shall not constitute grounds for modifying a support order.
(7) As used in this section, “joint custody” means an order of the court in which 1 or both of the following is specified:
(a) That the child shall reside alternately for specific periods with each of the parents.
(b) That the parents shall share decision-making authority as to the important decisions affecting the welfare of the child.