Occasionally, a dispute in volves both a grievance and an unfair labor
practice (ULP) charge. For example, bargaining-unit members might claim
certain work has been given to nonunion employees outside the bargaining
unit. The grievance would allege a violation of the contract on work
assignments, and the union might charge the employer with discrimination
based on uruon membership. To prevent "forum shopping" and to
reduce its caseload, the NLRB has adopted rules for deferring to arbitration
when a contract violation and a ULP are alleged simultaneously.