法則與權衡的爭論：排除條款與自我兌現分析

Abstract

本篇論文將Obstfeld(1996)所開創的匯率制度變革的研究方法，應用於Lohmann(1992)時序不一致分析架構，研究央行穩定物價的政策會依循排除條款策略，並且分析民眾對通貨膨脹的預期。經由本文分析發現，排除條款的設計可以限制央行採取權衡措施，藉此降低通貨膨脹傾向。\n然而，本文與Obstfeld(1996)發展的第二代通貨危機有類似的發現。我們發現在本文分析架構下會產生複均衡，說明央行會破壞原先承諾是因為民眾具有自我兌現特質。一旦民眾對通貨膨脹有更加悲觀的預期，會促使央行認為維持穩定物價政策成本過高，不得不放棄事先零通貨膨脹率的承諾，進而改採取權衡措施。\n我們發現有三種方法可以降低自我兌現危機發生的可能性：委任較為保守的央行官員、提高違約成本以及降低充分就業下之產出水準的扭曲程度。在維持零通貨膨脹率的法則政策下，這三種方法不僅可以降低民眾對通貨膨脹的預期，還可以提高央行對衝擊的容忍度，同時也能降低制度變革的機率。

Based on Obstfeld (1996), this thesis applies the research method of exchange rate regime switch to the time-inconsistency analytical framework of Lohmann (1992). We study that the central bank will implement an inflation-stabilization policy with escape clauses. Furthermore, we analyze the public’s inflation expectations under the rule. Through the analysis of this paper, it is found that the design of escape clauses can limit the central bank to adopt the discretionary policy, thereby reducing inflation bias.\nHowever, this paper has similar findings to the second generation of currency crises developed by Obstfeld (1996). We found multiple equilibria under our analytical framework. The central bank will break its commitment due to public self-fulfilling features. Once the public pessimistically expects inflation to worsen, the central bank considers that the cost of the rule of zero inflation is too high to keep the precommitment to zero inflation. Thus, it will adopt the measure of discretion.\nWe find three ways to reduce the probability of a self-fulfilling crisis: appointing more conservative central bankers, raising reputation costs, and reducing distortions in the level of output at full employment. Under the rule of zero inflation, these three methods can reduce inflation expectations and improve the central bank`s tolerance for shocks. They also reduce the probability of regime realign.