According to the Pennsylvania courts, where a collective bargaining agreement (CBA) allows a union to decide whether to arbitrate a grievance, the decision whether to appeal that arbitrator's determination is included even when the CBA is silent. This is not new law, but was reinforced in a decision from the PA Commonwealth Court yesterday. There, the court specifically said that:

the exclusive power to initiate arbitration includes the exclusive power to decide whether to appeal an arbitration award.

This is the case even when the CBA gives an employee the right to pick his or her own attorney and to prosecute the grievance on his or her own.

The case is Ray v. Brookville Area School District, 842 CD 2010 and can be found here.