In Richland Education Association v. Richland School District, 53 Pa. Commw. 367, 418 A.2d 787 (Pa. Cmwlth. 1980), the arbitrator held that "preferred substitutes," hired to work every day of the school year, were members of the bargaining unit. The collective bargaining agreement at issue in Richland identified members of the bargaining unit as "teachers, guidance counselors, and nurses," and the word "teacher" had been previously interpreted to mean full-time employees working as teachers. Richland, 418 A.2d at 788-790. The arbitrator reasoned that the School Board attempted to devise a unique classification, the "preferred substitute," to provide the District with certified teachers as full time employees and at the same time permit their exclusion from the bargaining unit. He concluded that the agreement contemplated that certified teachers who are full time employees shall be within the definition of the bargaining unit. The Court affirmed, finding the arbitrator's award to be rationally derived from the contract's use of the word "teacher." Richland, 418 A.2d at 788-791.