內生化懲罰與時序不一致

Abstract

本文以Barro and Gordon (1983b)所發展的時序不一致模型作為基礎，探討在央行官員於有限的任期中，若面臨時序不一致問題時，探討下一期內生化懲罰項存在與否，如何影響官員政策執行的程度（改變）。再者，討論政府如何透過選擇懲罰權重之手段，使央行官員執行的政策達到社會福利極大化的目標，並藉由數值模擬的方式分析相關外生參數（例如：時間偏好率、代表性個人保守程度等等）變動對政府選擇最適懲罰權重的影響。 經由本文分析，可以得到：利用內生化懲罰項的手段，的確可以有效抑制央行官員擴張產出的誘因，致使社會平均通貨膨脹率降低，但壓抑平均通貨膨脹率必須付出產出波動增加的成本。在追求社會福利極大化的目標前提下，經由數值模擬可得到，時間折現率與衝擊波動幅度，兩項外生參數與政府選擇最適懲罰權重具有反向關係；犧牲比率、社會扭曲程度與對產出穩定重視程度，三項外生參數與政府選擇最適懲罰權重具有正向關係。

Based on the model developed by Barro and Gordon (1983b), this thesis sets up a time inconsistency model featuring endogenous punishment. Specifically, this thesis assumes that monetary policy is delegated to a central banker whose preferences are the same as the representative agent, and addresses how the endogenous punishment mechanism will affect the decision of the central banker when the government office terms are finite. Then, this thesis deals with how the government chooses the optimal punishment weight to maximize the social welfare level. Finally, by means of numerical simulations, this thesis analyzes how the values of relevant exogenous parameters influence the optimal punishment weight chosen by the government. Our analysis finds that the introduction of endogenous punishment would lead to a reduction of the average inflation rate at the cost of a rise in the variability of output. In addition, to maximize the social welfare level, our numerical simulations show the following results: (1) the optimal punishment weight selected by the government is negatively related to the discount factor and the variability of shock; (2) the optimal punishment weight chosen by the government has a positive relationship with the sacrificed ratio, the extent of social distortion, and the extent placed by the central banker on inflation stabilization relative to output stabilization.