A: 在耶鲁读二年级的时候，我被Steve Berry教授面向研究生的产业组织（Industrial Organization，IO）课程深深启发，决定研究企业进入（firm entry）这一与行业竞争密切相关的方向。理解企业进入行为需要有较大的营业额数据，这样才能获得足够的实证观测。因此我不假思索地选择了零售业作为研究对象：这一行业每年都会有大量的企业进入、退出，是研究企业进入绝佳的选择。当我开始阅读零售行业的相关文献时，头条新闻里频繁出现的零售巨头沃尔玛引起了我的注意。沃尔玛的崛起故事引人入胜，因此我决定在我的求职论文（Job Market Paper）中研究它。

A: I was inspired by Prof Steve Berry’s graduate IO class at Yale when I was a second-year student and decided to study firm entry which is closely related to industry competition. Understanding firm entry requires high turn-overs so that there are enough empirical observations. It did not take me very long to decide that the retail industry, with plenty of entries and exits each year, would be a perfect industry to study entry. As I started reading about the retail industry, I noticed the frequent headline stories about the largest retailer Wal-Mart. The rise of Wal-Mart is a fascinating story that I decided to work on in my job market paper.

A: 现在回想，我十分幸运能够发现折扣零售行业的崛起这一重要现象。折扣零售行业在20世纪60年代之前几乎不存在，但在被电子商务行业超越之前，在20世纪60年代到21世纪的这几十年里，它一度成为发展最迅猛的零售部门。因为几乎没有学术论文研究过这一重要现象，我的求职论文或多或少地由此成为了一篇有影响力的论文。因此，我认为能做出有高度影响力研究的途径之一，就是能够发掘重要变化和趋势。

A: In hindsight, I was lucky and identified an important phenomenon–the rise of the discount retail sector. The discount sector was close to non-existent prior to the 1960s and became the fastest-growing retail sector for the following decades from the 1960s to 2000s until it was taken by the e-commerce sector as the fastest growing sector. There were almost no academic papers that studied this important phenomenon, and my job market paper became influential partly because of this. Being able to identify important changes and trends is one way to produce highly impactful research.

A: 我花了将近三年时间来收集美国1962年（沃尔玛和凯马特创始之年）至1977年折扣店进入和退出的年度数据，其中我必须和美国各地的不同图书馆申请折扣店目录的副本并制作超过十万页的复印件，之后再手动录入复印件上的数据，这项工作非常耗时，所以我也只设法录入了我这篇文章里所使用的两年的数据。

模型估计同样非常具有挑战性。我需要学习格理论（Lattice Theory）来证明均衡在一个具有战略考虑（strategic considerations）和空间相依（spatial inter-dependence）的模型中的存在性（我从未在课堂上接触过格理论，在此感谢推荐我去学习这一理论的Hanming Fang教授）。求解模型也十分困难，有一次我得到了一个可行的求解算法，却遇到了算力的限制，当年并没有运算速度足够快的电脑能帮助我在准备进入就业市场之前及时解决这个模型。因此，在21世纪初，我率先在耶鲁社会科学计算机室推动了并行运算。

A: It took me close to three years to collect data on the annual entry and exit of discount stores in the U.S. from 1962 (the birth of Wal-Mart and Kmart) and 1997. I had to request from many libraries across the country for copies of the discount store directories and made more than 100,000 pages of photocopies of these directories. Then I had to enter the data from the photocopies manually, which was very time-consuming. I only managed to enter data for two years, which was what I used for this paper. 

Estimating the model also turned out to be challenging as well. I had to learn the lattice theory (which I never learned in classes and thanks to Professor Hanming Fang who suggested that I look into it) to prove the existence of equilibria for a model with strategic considerations and spatial inter-dependence. Solving the model was hard as well. Once I figured out a feasible solution algorithm, I ran into computational constraints. There were no PCs fast enough that could solve the model in time for me to get ready for the job market. I was the first user at Yale’s social science computer lab to push for parallel computing in the early 2000s.

A: 我的建议是：保持开放的心态，去寻找新现象或重要趋势，不要轻言放弃，毕竟研究(research)就是不断重复地寻找、再寻找（re-search）的过程！

A: My advice: keep open-minded, search for new phenomena/important trends, and do not easily give up. Research is repeated search (re-search)!

学者简介：贾攀乐（Panle Jia Barwick）现为康奈尔大学经济系教授，康奈尔中国经济研究所（CICER）联合主任。贾攀乐教授的研究领域主要包括产业组织、应用微观经济学、应用计量经济学，她对环境经济学尤为感兴趣。她的学术兼职还包括美国国家经济研究局（NBER）研究员，VoxChina和Journal of Urban Economics编委会成员，Journal of Industrial Economics主编，Rand Journal of Economics和International Journal of Industrial Organization副主编等。

※本文摘自公众号Impactful Research, 侵权必删。