Collective bargaining agreements are valid for employees who are members of the trade union concluding the agreement as well as for the employer who concludes it or is a member of an employers' association which has agreed to the agreement. However, with collective bargaining coverage in decline, both the state and the parties to such agreements may have an interest in extending the effect of collective bargaining beyond this circle. In her study, Kyra Klocke sets out the constitutional framework for legislative and collective bargaining policy measures with outsider effects.