讲座题目：Optimal Size and Composition of Government Spending in Small Open Economies（小型开放经济中最优政府开支）

主讲人 ：杜清源 莫纳什大学经济学系

讲座时间：2023年12月6日14:30

讲座地点：学院210

讲座内容摘要：

In this paper we study how government spending should adjust when responding to productivity shocks. We do so in the context of a small open economy with tradable and non-tradable sectors, fixed exchange rate, downward nominal wage rigidities, and two government spending programs. In our model changes in government consumption (non-productive spending) and government investment (productive spending) influence aggregate demand and contribute to short-run economic stabilization. Moreover, through productive spending, it can also impact productivity, which in turn affects aggregate supply and long-run output. We consider three government spending policies: (i) a Ramsey policy where the size and composition of government spending are optimally adjusted; (ii) a constant share policy where the composition is kept unchanged; and (iii) an optimal government consumption policy where government consumption can be changed, but public investment is kept constant. Our simulation results show that changes in the size and composition of government spending can effectively reduce the impact of negative productivity shocks. In particular, it can decrease involuntary unemployment, and help smooth private consumption. However, these effects are asymmetric during the boom-bust episodes. The Ramsey and optimal government consumption policies appear to be more effective in smoothing the adverse productivity shocks and maintaining low unemployment. Meanwhile, aggressive responses in public investment to productivity shocks deliver higher welfare.

我们在本文中研究经济周期中政府如何选取最优政府开支来应对经济中存在的冲击。我们通过建立一个两部门模型（可贸易部门以及不可贸易部门），研究在固定汇率下当经济体面临名义工资刚性的情况下政府的最优政策行为。在我们的模型中，政府通过调整政府消费（非生产性支出）和政府投资（生产性支出）的来影响总体需求，促进短期经济稳定。此外，政府通过生产性支出影响经济的生产效率，进而影响总体供应和长期产出。我们考虑三种政府支出政策：(i) Ramsey最优政策，即政府支出的规模和构成都得到了最优调整；(ii) 固定份额的政府开支政策，即政府投资和政府消费在经济周期中比重保持不变；以及(iii) 最佳政府消费政策，即政府消费可以更改，但公共投资保持不变。我们的模拟结果显示，政府支出的规模和构成的变化可以有效减少负面生产力冲击的影响。特别是，它可以减少非自愿失业，并帮助平滑私人消费。然而，这些效果在繁荣-衰退时期是不对称的。Ramsey政策和最优政府消费政策似乎在平滑不利的生产力冲击和维持低失业方面更为有效。同时，对生产力冲击的公共投资的积极响应带来了更高的福利。

主讲人学术简介：

Dr. Qingyuan Du is currently a Senior Lecturer in the Department of Economics at Monash University. He obtained his Ph.D. from Columbia University in 2011. His primary research areas are international economics and macroeconomic policies. Dr. Du has published his research in well-known international refereed journals, including the Journal of International Economics, Review of Economic Dynamics, European Economic Review, Journal of International Money and Finance, among others.

杜清源博士目前是莫纳什大学经济学系的高级讲师。他于2011年从哥伦比亚大学获得经济学博士学位。他的主要研究领域是国际经济学和宏观经济政策。杜博士已在著名的国际审稿期刊上发表了他的研究，包括《国际经济学杂志》、《经济动态评论》、《欧洲经济评论》、《国际货币与金融杂志》等。