公債的發行對經濟成長的影響究竟是利或弊,需視其發行的原因及目的而定,一國公債佔國內生產毛額比值之高低,為影響經濟成長的重要關鍵,實證文獻亦證實此二者之關係存在一門檻值,在低於此門檻的範圍內,兩者間有正向關聯;反之,則呈現負向關聯。以往實證文獻對於門檻值的估計係採將公債比粗略分為三至四個水準,並就各個水準分別進行迴歸估計,不同地區的門檻值亦不相同。由於目前亞洲地區似乎尚未有此議題的實證文獻,故本研究參考以往過去文獻的研究方式,將其應用於亞洲地區國家。 本研究以1985至2007年間亞洲地區十個樣本國家為觀測對象,利用動態追蹤模型(dynamic panel data model)探討公債比對經濟成長的影響,並計算其門檻值。由於各樣本國家間經濟發展的程度不同,本文粗略地將樣本國家區分成先進國家及發展中國家等二類。另外,亦透過結構性檢定將亞洲金融風暴及網路泡沫化發生前後的樣本期間分割以進行研究。 在1985至2007年的全樣本期間下,全樣本國家下的門檻值為100%至125%,信賴區間的下界約為70%,代表公債比若超過此水準,其對經濟成長將發揮抑制的效果。若將國家區分為兩類,發展中國家的門檻值約為75%至85%;先進國家則無顯著結果。在1985至1996年子樣本期間下,全樣本國家亦存在此倒U型關係,門檻值較全樣本期間時的為低,若將國家區分為兩類,皆無顯著的估計結果。當子樣本期間為2002至2007年時,全樣本國家下的門檻值約為120%,信賴區間下界約為110%,國家分類下的發展中國家及先進國家,皆存在顯著的結果,推論可能由於經歷1997年的亞洲金融風暴及2000年的網路泡沫化,各國經濟成長率皆大幅波動,政府被迫藉由發行公債,大量增加政府支出以提振經濟,導致各國財政結構產生重大的改變。 在公債比對經濟成長影響之管道上,本文探討公債比與民間儲蓄、總投資及利率之間的線性及非線性關係,證實公債的確藉由不同路徑間接抑制經濟成長。
The impact of government debt on growth depends on the reason and the purpose it issues. At moderate level, debt can improve welfare and enhance growth, but beyond a certain level, debt can be damaging. This research applies dynamic panel data model to investigate the link between government debt-to-GDP ratio and real per capita GDP in ten Asian countries over the period from 1985 to 2007. It finds a non-linear impact of debt on growth with a turning point in different time periods and different sample countries we choose. In 1985 to 2007, for all countries (sample), the threshold is around 100% to 125% of GDP, and the confidence intervals for the debt turning point is around 70% of GDP which suggests the negative relationship between debt and growth may start from this level; for developing country, it lies between 75% to 85% of GDP; but advanced country doesn’t show significant results. In 1985 to 1996, for all countries, the concave relationship (inverted U-shape) exists; however, for developing and advanced country, no significant results exist. In 2002 to 2007, for all countries, the threshold is around 120% of GDP, and the confidence intervals for the debt turning point is around 110% of GDP; for developing and advanced country, the concave relationship also exists. The channels through which government debt(level or change) is found to have an impact on economic growth rate are: (i) private saving; (ii) total investment; (iii) interest rate.