We analyse the policy of an independent central bank in a monetary union. The monetary policy equilibrium, prevailing under either discretion or commitment, is analogous to the one country case, although the stabilization policy is less than optimal for each single country in the monetary union. The extent of optimality of the monetary rule changes with the cross-country heterogeneity in economic shocks. Heterogeneity of preferences implies, that in a dynamic setting there is variation in the incentives of each member country. A country with a low target level of output or output cost weight might not reap any benefit from a deviation from the commitment equilibrium. The commitment policy can be enforced with a proper definition of the inflation expectations rule. With homogeneous preferences the advantages and disadvantages of the monetary union commitment policy relatively to the own discretionary one, for any new candidate or existing member country, are a function of its relative size and degree of asymmetry.

我们分析了货币联盟中独立中央银行的政策。尽管在货币联盟中每个国家的稳定政策都不是最优的，但在自由裁量权或承诺下普遍存在的货币政策均衡类似于一个国家的情况。货币规则的最优程度随着经济冲击中跨国异质性的变化而变化。偏好的异质性意味着，在动态的环境中，每个成员国的激励机制都有差异。目标产出或产出成本权重较低的国家可能无法从背离承诺平衡中获得任何收益。可以通过正确定义通货膨胀预期规则来实施承诺政策。