勞動供給的所得效果與信念驅動的景氣波動：通貨膨脹指標的分析

Abstract

本文以Benhabib and Farmer (1994)和Itaya and Mino (2003)的模型架構為基礎，建立一個有生產外部性的貨幣外生成長模型。在此架構下，分析政府採行釘住通貨膨脹率目標時，動態體系是否存在非確定性。如果經濟體系存在非確定性，則引入貨幣到Benhabib and Farmer (1994)的模型時，是否會改變Benhabib and Farmer (1994)對於發生信念驅動的景氣波動所要求的規模報酬遞增程度。此外，將再進一步分析在有生產外部性的貨幣外生成長模型中，勞動供給所得效果與信念驅動的景氣波動之間的關係。最後本文將討論政府提升通貨膨脹率目標對於經濟體系長期均衡的政策效果。\n依據勞動供給是否存在所得效果可得到以下兩點結論：(1)在勞動供給存在所得效果時，如果生產外部性足夠大，即使政府採行釘住通貨膨脹率目標仍然會出現信念驅動的景氣波動，其發生信念驅動的景氣波動所要求的規模報酬遞增程度與Benhabib and Farmer (1994)相同。無論經濟體系是否為確定性，當政府提升通貨膨脹率目標時，在長期均衡時皆會造成資本累積減少。(2)在勞動供給不存在所得效果時，無論生產外部性大小如何，皆不會出現信念驅動的景氣波動。在生產外部性較小時，政府提升通貨膨脹率目標會造成長期均衡的資本累積減少；而在生產外部性較大時，政府提升通貨膨脹率目標會造成長期均衡的資本累積增加。

Based on the framework of Benhabib and Farmer (1994) and Itaya and Mino (2003), this paper establishes a monetary exogenous growth model with production externalities, in which the government implements a monetary policy of inflation rate targeting. Under this framework, this paper investigates whether the dynamic system exhibits indeterminacy and whether the degree of increasing return to scale required for indeterminacy is different from which in Benhabib and Farmer (1994). In addition, this paper investigates whether the income effect on labor supply is a important condition for belief-driven business cycles. And this paper also discusses the long-term monetary policy effect when the government raises the inflation rate targeting.\nTwo main findings emerge from the analysis. First, when income effect on labor supply exists, the economy with sufficiently large positive production externalities in technology may exhibit indeterminacy. And the degree of increasing return to scale required for indeterminacy is the same as in Benhabib and Farmer (1994). Regardless of whether the economy is indeterminate or not, a rise in the inflation rate may lower the capital accumulation in the long-term equilibrium. Second, when income effect on labor supply is not present, regardless of the degree of increasing return to scale, the economy is always determinate. If the positive production externalities in technology are not sufficiently large, a rise in the inflation rate may lower the capital accumulation in the\nlong-term equilibrium. Conversely, If the positive production externalities in technology are sufficiently large, a rise in the inflation rate may raise the capital accumulation in the long-term equilibrium.