A.R.S. § 12-1871: Determination of maintainability

A. After the commencement of an action that is brought as a class action and after a hearing, the court shall determine by order whether the action is to be maintained as a class action. The court may condition, alter, amend or withdraw its order at any time before the decision on the merits.

B. If the court finds that an action should be maintained as a class action, the court shall certify the action in writing, shall set forth its reasons as to why the action should be maintained as a class action and shall describe all evidence in support of its determination.