Ernest Liu谈QJE2019创作心得 Ernest Liu on QJE (2019)
本文最初于 2021 年 9 月 28 日 发布于微信公众号 Impactful Research；2026 年 4 月 28 日 同步至本网站。
Originally published on the WeChat official account Impactful Research on 2021-09-28; mirrored to this website on 2026-04-28.
来源：Google图文
又是找工作的季节，我们决定开辟一个新的专题，采访那些过去几年中市场上冉冉升起的新星，听他们分享一篇有影响力的“就业市场论文”背后的故事。
这个系列的第一篇文章，我们邀请到普林斯顿大学经济系的助理教授Ernest Liu分享他的job market paper的创作历程和对青年学者及博士生的建议。Ernest 2017年毕业于麻省理工大学 (MIT)，他的job market paper “ Industrial Policies in Production Networks ”发表在2019年的 Quarterly Journal of Economics 。这篇文章非常巧妙地结合了理论与实证研究，基于生产网络理论来理解产业政策背后的逻辑，尤其是解释为什么很多发展中国家政府会对上游产业进行强力支持。这篇文章填补了文献中关于产业政策研究的一个重要空白，激发了学者们的广泛讨论。
除了产业政策，Ernest的研究还关注增长、贸易、金融及中国经济等多个领域。他的另外一篇论文“ Low Interest Rates, Market Power, and Productivity Growth ”发表于 Econometrica ，解释了较低的长期利率水平是如何促进市场集中度增加并降低生产率增长的。他关于发展金融学的理论研究发表于 Journal of Financial Economics 和 Review of Financial Studies 。他最近的一篇工作论文试图探究国家的经济利益如何影响他们的政治行为，他发现当一个国家经济上更依赖其贸易伙伴时，其政治行为也会与之趋同。他最新的方法论研究为动态生产网络和动态空间经济学的研究提供了一个通用的可解框架。
以下是Ernest Liu教授分享的关于Industrial Policies in Production Networks (QJE 2019) 这篇文章的创作历程。原访谈为英文问答 ，我们对Ernest Liu教授的回答作了中文翻译。
**Q: How did you identify this research question?**
Q: 您是怎样发现这一研究问题的？**
A : Growth and development policies have always fascinated me, long before graduate school. I think this interest was primarily shaped by having witnessed China’s economic transformation. I have been living abroad since 2002, right about when the economic transformation started, and I have just been consistently in awe of China’s development every time I visit home. Understanding what causes transformative growth and the role of government policies is what motivated me to become an economist.
A : 也许是因为亲眼目睹了中国的飞速发展，我在读博士之前我就对经济增长和发展政策相关问题感兴趣。我从2002年起在国外生活，而那恰好也是中国经济转型开始的时候。我每次回国都对中国的发展感到震撼。我希望能够理解国家变革式增长的原因以及政府政策在其中所起的作用，这也是我致力于经济学研究的最初动力。
A : I have been reading and thinking about Chinese growth throughout graduate school. The papers “Growing Like China” in the AER and “Grasp the Large, Let Go of the Small” in Brookings had a significant influence on my interest in the role of state-owned firms. I was particularly puzzled by the fact that modern state-owned firms in China tend to occupy upstream sectors, for example, chemicals, metals, and heavy machinery sectors. While it is easy to rationalize this fact as an incidental outcome—for example, perhaps state-own firms tend to be in sectors with certain characteristics (e.g., increasing returns, natural monopolies) and upstream sectors just happen to have these characteristics—I felt unsatisfied by such explanations, and I was hoping to understand how cross-industry connections could determine the role of state-owned firms and industrial policy more broadly. I came to learn that Japan and South Korea promoted the same set of upstream sectors during their high-growth decades, and thus state-led promotion of upstream sectors seems to be a common trait in the “East Asian miracle”. Many of the policy documents in China and other East Asian economies explicitly define “strategic” sectors of the economy as being well-connected to others, and that “pillar” industries should support the whole economies. I also found out that early pioneers in economics, such as Albert Hirschmann, have put forth arguments for the importance of input-output linkages for development policies, though at a time before the invention of modern economics. That was when I decided to revisit this question—how to conduct developmental policies when industries form input-output linkages—using modern tools I learned from graduate school.
A : 在博士阶段我阅读了很多关于中国经济增长的文章，也做了很多自己的思考。AER里的“Growing Like China”和Brookings里的“Grasp the Large, Let Go of the Small”两篇论文极大增加了我对研究国有企业在经济增长中所起的作用这一问题的兴趣。当时有一个发现是中国现代国有企业倾向于占有上游产业，比如化工、金属，和重机械。这种现象可以被归于偶然——比如国有企业可能倾向于在具有某些特征（如，边际收益递增和自然垄断）的产业投资，而上游产业正好具备这些特征。但是我对这些解释并不满意：我想理解产业间的联系与网络本身如何决定了国有企业在经济活动中的角色以及如何影响了政府的产业政策。之后我了解到日本和韩国在高速增长的几十年里，推动的是同一套上游产业，因此国家主导的上游产业支持似乎是“东亚奇迹”的共同特征。中国和其他东亚经济体的许多政策文件明确界定了经济的“战略”产业应是与其他产业紧密联系的产业，以及“支柱”产业应能够支撑整个经济体。我还发现，早期经济学先驱，如阿尔伯特•赫斯曼(Albert Hirschmann)，已经论述了投入-产出联系对发展政策的重要性，尽管当时现代经济学还未成型。因此，我决定重新审视这个问题——当产业间形成产业链以及投入-产出网络时，如何运用我博士阶段学到的现代工具来制定经济发展政策。
**Q: From your perspective, what are the main reasons that make this paper a very successful job market paper?**
Q: 从您的角度来看，是什么使这篇论文成为一份非常成功的就业市场论文?
A : Not sure if it is a successful “job market” paper, but it is a paper I am very happy to have written for the following reasons. To me, how to conduct industrial policy is one of the most important questions in economics, especially for developing economies with strong governments such as China. It is also a question that has been dormant in the academic literature for many years if not decades. I was really eager to provide an answer to satisfy my own curiosity, but the fact that this topic is important yet under-studied also makes studying it very high return and professionally rewarding. I was also very fortunate to have received the right training in graduate school to execute the project well. I think the end product has a novel economic insight about industrial policy, that government promotion of upstream sectors in distorted economies could improve aggregate efficiency; it also has non-trivial theoretical results that are applicable to the broader literature on production networks, as well as extensive empirical support of my economic insights using many data sets from China and South Korea.
A : 我不确定这是否是一篇成功的“就业市场”论文，但我很高兴能把它写出来，原因如下：在我看来，如何制定产业政策是经济学中最重要的问题之一，特别是对于中国这样拥有强大政府的发展中的经济体而言。这也是一个在学术文献上停滞了多年甚至几十年的问题。从个人的角度我对这个问题很有兴趣，从专业的角度这个问题既重要又少有现代的文献，也使得研究它的回报很高。我也很幸运地在博士阶段接受了正确的训练使我能够很好地完成这个研究项目。我认为这篇论文对产业政策有新颖的经济学见解，即在一个被扭曲的经济体中，政府对上游部门的支持可以提高总体效率；它也有适用于更广泛的生产网络研究的理论成果，以及对我提出的理论的客观支持，其中包含了很多中国和韩国的数据集合。
**Q: What was the greatest challenge during the writing and revision of the paper?**
Q: 在这篇文章写作与修改过程中最大的挑战是什么？**
A : The topic of industrial policy has been dormant for a reason: the instinctive, knee-jerk reaction of many mainstream academic economists is that industrial policy is bad, these policies are distortionary, and government bureaucrats cannot possibly know how to design good policies. This reaction and prior belief are so strong that industrial policy studies tend to be viewed unfavorably, even after controlling for quality. I experienced this resistance, and bulk of the challenge of publishing this paper is to overcome this resistance. I think perseverance was key: even very strong prior beliefs can be changed through repeated persuasions. I actively sought any opportunity to present the paper and discussed the topic with as many economists as I could. Eventually, I found the right audience and had enough support of the paper to get it published, and there are many people to thank during this process.
A : 产业政策的研究一直处于停滞状态是有原因的：许多主流经济学家下意识的反应是，政府不应该干预市场的运行；政府官员不可能制定出比自由市场更好的产业政策，因此没有必要研究这个问题。由于这种先入为主的观念，即使是高质量的产业政策研究仍然难被重视。这种阻力是发表这篇论文过程中遇到的最大困难。我认为坚持是关键：即使是非常强烈的主观意识也必须通过反复交流而改变。我积极地通过学术报告会宣讲论文，并尽可能与许多的经济学家讨论这个话题。最终，我找到了合适的受众，得到了足够的支持，论文得以发表。我要感谢很多人在这个过程中对我的帮助。
**Q: Do you have any advice for PhD candidates as well as junior scholars on how to produce high-quality research?**
Q: 您对博士研究生和青年学者开展高质量的研究有什么建议？
A : First, invest in your human capital. Expand your skillset, so that you can work on a broader set of questions. Read extensively, so that you know how high-quality research is done and where the literature is. I would also like to quote Alp Simsek on this: “Take every academic task seriously, no matter how unimportant it might seem at the time. Doing academic tasks is like going to the gym regularly. It makes sure that you are prepared when the more important tasks arrive. It also creates good working habits. If you are not sloppy with the little tasks, the chances are this will become your second nature and you will be very careful also with the more important tasks.”
A : 首先，投资自己的人力资本，开拓自己的眼界，提高自身素质。要扩展研究上的硬技能，这样你就可以解决更广泛的问题。要大量的阅读，关注经济学领域前沿的课题，这样你就了解什么是高质量的研究。引用Alp Simsek的话：“严肃认真地对待每一个学术任务，无论它在当时看起来多么无足轻重。完成学术任务就像定期去健身房。它确保你在更重要的任务到来之时已做好准备。它还能培养良好的工作习惯。如果你在小任务上不马虎，很可能认真就会成为你的第二天性，你也会在更重要的任务上非常细心。” 如果你在细节上认真对待，就会养成良好的习惯，那么在重要研究项目的把握上就会游刃有余。
A : On topic selection, my advice is always follow your interest. Research is a long process—it takes many years from starting a project to having it published, and the authors have to overcome many kinds of difficulties, including both the execution of the project and finding a path in the editorial process. I think the only way to keep myself motivated during this long process is to work on the projects that I am truly passionate about. Of course, finding one’s passion may not be straightforward either, especially for PhD students who are still trying to learn different areas of economics. My personal trick for coming up with new ideas is to always ask “what is the most important topic that my skillset allows me to work on”. The ideas coming out of these introspections are usually on topics that I am very passionate about but do not already have a crowded literature, meaning there is more room for novel contributions on these topics.
A : 在选题上，我的建议是选择自己真正感兴趣的问题去做研究，这样在研究中碰到困难也会有坚持下去的动力。研究是一个漫长的过程——从开始一个项目的雏形，到研究、深入、修改、发表，常常需要多年时间的反复磨合，整个过程会碰到各种困难，有时就像坐过山车，有时又像在迷宫里出不来，期间的沮丧和兴奋是相伴的，碰到困难需要有足够耐心和坚韧的毅力来支撑。因此在研究过程中，对项目抱有很大兴趣就是坚持下去的源动力。当然，找到自己真正感兴趣项目也不是一件简单的事，尤其是对还没有确定研究方向的低年级博士生来说会有些困难。我产生新想法的诀窍是自问“我的技能允许我研究的最重要的主题是什么”。这些自省所产生的想法通常是我非常感兴趣又不会过于热门的话题，也就意味着在这些话题上有更多空间来容纳新的观点及理论。
**Q: Do you have any advice for PhD students on their PhD study?**
Q: 您对攻读博士学位的学生有什么建议吗?
A : Invest in your human capital, as I mentioned above. Talk to your classmates; exchanging ideas and debating with my classmates were the most enjoyable part of graduate school. Also try to find a support group of family and friends; PhD study can be challenging, both physically and mentally, and you may need a support group to help you through.
A : 首先是我上面提到的，广泛的阅读、汲取知识来扩展自身的能力。还有很重要的是多和你的同学讨论及分享，在学术辩论中交流思想，各种思维会碰撞出火花，给你的研究带来很多启发。和同学的商讨与辩论是我博士期间最有意思的经历，有时困惑的问题会在辩论中豁然开朗。同时要多和家人和朋友交流，及时调整心理状态和情绪。博士学习阶段，体力和精神上都会遇到很多压力，会有各种困难和挑战，你要学会调整，并寻求大家的帮助。
Q: Do you have any advice for job market candidates in terms of job hunting?
**Q: 您对求职者有什么建议吗?**
A : The job market is still a mystery to me. If I can dial back in time and talk to myself before the job market, I would tell my younger self, “The job market process can be random and idiosyncratic. Be perseverant; being in academia comes with the privilege for a lifelong pursuit of knowledge, and do not get too affected by short-term ups and downs.”
A : 如果我能给找工作之前的自己打个电话，我会告诉那时的我：“找工作的过程有很多不确定因素，会碰到很多困难，要自信、要坚持。在学术界工作有终身追求知识的机会，不必太在意短期的起起伏伏。”
学者简介：Ernest Liu现为普林斯顿大学经济系助理教授。他2017年毕业于麻省理工大学（MIT）。Ernest Liu教授的研究领域包括增长、贸易、金融及中国经济等。他的文章曾发表于 Quarterly Journal of Economics ， Econometrica ， Journal of Financial Economics ， Review of Financial Studies 等国际顶级经济学和金融学的期刊。
参考文献：
Liu, Ernest. “Industrial policies in production networks.” The Quarterly Journal of Economics 134.4 (2019): 1883-1948.
Liu, Ernest, Atif Mian and Amir Sufi. “Low Interest Rates, Market Power, and Productivity Growth.” Forthcoming, Econometrica
Hsieh, Chang-Tai, and Zheng Michael Song. Grasp the large, let go of the small: The transformation of the state sector in China. No. w21006. National Bureau of Economic Research , 2015.
Song, Zheng, Kjetil Storesletten, and Fabrizio Zilibotti. “Growing like China.” American Economic Review 101.1 (2011): 196-233.
| 责任编辑 | 秦雨、李明、Cindy、韩亚婕 |
| 校对 | Ernest Liu |