基于历史信息锚定预期形成机制的货币政策有效性

Monetary policy effectiveness based on the expectation of historical information anchoring

文章首先通过数理模型探讨了历史信息锚定预期对最优相机抉择和规则货币政策的制定和政策有效性的影响,然后结合数值模拟比较分析了历史通胀信息外生给定和内生政策决定两种情况下,两种类型的最优货币政策和无货币政策情况下的社会福利.研究结果表明：从平均意义上看,历史信息锚定的存在在历史通胀较小的情况下会提高最优相机抉择货币政策的有效性,但会削弱规则货币政策的有效性.从一期政策有效性来看,货币政策实行即使在价格灵活调整的情况下也总是有效的,并且不管锚定程度如何,规则的货币政策有效性要略大于相机抉择货币政策的有效性.但从多期政策有效性看,如果存在跨期历史信息锚定,针对供给冲击实行的货币政策,政策有效性在一期提升社会福季利后,会产生后续持久的负效应,中央银行的货币政策制定应避免陷入政策自我实现的通胀预期陷阱.

The paper first discussed the influences of the historical information anchoring on the optimal discretionary monetary policy and monetary policy rule. Then, combined with the method of numerical simulation, it compared the social welfare of two kinds of optimal monetary policy and non-monetary policy in two cases — the historical inflation information is exogenously given or endogenously determined by the policy decision. The results showed that, on the average, the existence of the historical information anchoring will improve the effectiveness of the optimal discretionary monetary policy on the condition of low historical inflation, but weakens the effectiveness of the monetary policy rule. In view of oneperiod policy effectiveness, the monetary policy is effective even under the condition of flexible price adjustment. Regardless of the anchoring degree, the monetary policy rule is more effective than the optimal discretionary monetary policy. But in view of multi-period policy effectiveness, if the inter-temporal information anchoring exists, the monetary policy will give birth to sustained negative effect after improving social welfare in the first period. It is necessary to avoid the expectation trap of the policy self-fulfillment when the central bank wants to implement a monetary policy.