¶14 By granting deference to agency interpretations, the court has not abdicated, and should not abdicate, its authority and responsibility to interpret statutes and decide questions of law. Some cases, however, mistakenly fail to state, before launching into a discussion of the levels of deference, that the interpretation and application of a statute is a question of law to be determined by a court.  In any event, it is the court’s responsibility to decide questions of law and determine whether deference is due and what level of deference is due to an agency interpretation and application of a statute. The court determines the appropriate level of deference by comparing the institutional qualifications and capabilities of the court and the agency by considering, for example, whether the legislature has charged the agency with administration of the statute, whether the agency has expertise, whether the agency interpretation is one of long standing, and whether the agency interpretation will provide uniformity and consistency.¶15 Furthermore, giving deference to the agency interpretation does not mean that the court accepts the agency interpretation without a critical eye. The court itself must always interpret the statute to determine the reasonableness of the agency interpretation. Only reasonable agency interpretations are given any deference.
The court goes on to discuss at some length the three levels of deference of agency interpretations of statutes in adjudicative matters, ¶¶16-20. Additional discussion found in 3-Justice concurrence in separate case, Hilton v. DNR, 2006 WI 84, ¶¶47-69 which identifies and seemingly laments the trend in favor of judicial deference to administrative decisions.