There is no standard that requires a match between a faculty member's Ph.D. field and teaching field. The standard requires that the faculty member is qualified to teach in the field. If that qualification does not follow directly from the field of the Ph.D., other background can demonstrate that the faculty member is academically qualified.

The person may have completed additional graduate course work or personal study sufficient to provide a base for participation in the teaching, intellectual contribution and service sought by the school. Professional and research experience may provide necessary applied background. The greater the disparity between the field of academic preparation and the area of teaching, the greater the need for supplemental preparation.

Normally, it is not sufficient to show previous teaching experience in the field. Such a justification would be tautological (the person is qualified to teach in this field because the person has taught in this field).