经济政策不确定性与全球贸易低速增长——基于引力模型的分析

不断上升的经济政策不确定性能否有助于解释全球贸易的低速增长呢?文章利用贸易引力模型,从沉没成本、实际需求和预期三种渠道探讨了经济政策不确定性对国际贸易的影响,然后利用国别配对数据对其进行了实证研究.结果表明:(1)贸易规模不但受到进口国经济政策不确定性绝对水平的影响,也受到其相对增速的影响,但出口国经济政策不确定性的影响不显著;(2)经济政策不确定性的贸易抑制效应与进口国的宏观经济状态有关,在失业率较高时期表现更为明显;(3)经济政策不确定性对贸易的影响存在门限特征,不确定性程度较高时期的影响明显高于程度较低时期的影响.文章不但有助于解释2008年金融危机后全球贸易的低速增长,也指出了国际间的政策合作和反对"逆全球化"进而降低经济政策不确定性,是实现全球贸易增长的重要途径.

Economic Policy Uncertainty and Low Growth of International Trade: An Analysis based on the Gravity Model

Summary: This paper first theoretically analyzes that Economic Policy Uncertainty (EPU) will inhibit trade from three sources:sunk costs,actual demands,and expectations. Then,based on the traditional gravity model,it introduces EPU to the model and uses country-pair quarterly data to empirically study the extent of the trade impact of EPU,and further discusses whether there are differences in the degree of influence of EPU on trade under different conditions. The conclusions of this study are as follows:(1) The absolute value and growth of EPU both have an ad-verse impact on the trade scale,but the impact of exporter's EPU index is insignificant;(2) EPU's inhibitory effect on trade is related to macroeconomic status of importers,especially in countries with high unemploy-ment;(3) There is a threshold effect of EPU on trade,and the marginal effect is significantly larger at a high level of EPU than at a low level of EPU. The conclusions of this paper provide important inspirations for the stable growth of global trade:under the current situation of relatively low growth of international trade,reducing the level of EPU is an important way to achieve stable growth of global trade and overcome existing difficulties. Besides,the international com-munity should attach great importance to the detrimental effects of EPU on trade and adopt effective measures to reduce EPU. Specifically,countries should firmly oppose the "reverse globalization",and strengthen the co-ordination of international economic policies and jointly safeguard multilateral cooperation mechanisms. The contributions of this paper are as follows:First,a relatively comprehensive mechanism of EPU's im-pact on trade is proposed. This paper believes that as a broader measurement of policy uncertainty,EPU may not only affect the sunk costs of trade and entry and exit decisions,but also affect the scale of external demand facing traders and the expectations of traders. Second,through country-pair data,this paper empirically ana-lyzes the trade inhibition effect of EPU,and points out that the impact of EPU has a non-linear characteristic, and the degree of its influence depends on both the macroeconomic status and the degree of EPU itself. Third, the conclusions of the study have strong policy implications. This study not only provides a new explanation for the low-speed growth of global trade in recent years from the perspective of EPU,but also provides more theoretical basis for countries to strengthen the policy cooperation and maintain the multilateral system.