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1. 压力如何影响跨性别的绩效和竞争力
许多重要的职业事件（例如考试和面试）都包含竞争和压力因素，因此，针对这些因素的性别差异可能有助于解释劳动力市场的性别差距。在实验室实验中，本文使用“特里尔社交压力测试”（Trier Social Stress Test）测量了心理社交压力，并通过测量唾液皮质醇水平和心率来确认这是有效的。受试者在竞争和计件工资的激励下执行真实的任务，本文激发了竞争的意愿。本文发现，在受到比赛奖励的补偿后，处于紧张状态的女性的表现要比对照组的女性差，而在计件奖励下则没有差异。对于男性，压力不会影响竞争或计件工资下的工作量。竞争意愿中的性别差距不受压力的影响，但压力会降低总体竞争力，这与女性的表现有关。本文的结果可以解释竞争条件下绩效的性别差异，这对公司的雇用实践和激励结构具有影响。
Because many key career events, such as examinations and interviews, involve competition and stress, gender differences in response to these factors could help to explain the labor market gender gap. In a laboratory experiment, we manipulate psychosocial stress using the Trier Social Stress Test and confirm that this is effective by measuring salivary cortisol level and heart rate. Subjects perform in a real-effort task under both tournament and piece-rate incentives, and we elicit willingness to compete. We find that women under heightened stress perform worse than women in the control group when compensated with tournament incentives, whereas there is no treatment difference under piece-rate incentives. For men, stress does not affect output under competition or under piece rate. The gender gap in willingness to compete is not affected by stress, but stress decreases competitiveness overall, which is related to performance for women. Our results could explain gender differences in performance under competition, with implications for hiring practices and incentive structures in firms.
参考文献：Cahlíková, J., Cingl, L., & Levely, I. (2020). How stress affects performance and competitiveness across gender. Management Science, 66(8), 3295-3310.
2. 通过自愿与强制向投资者披露来管理供应商的社会和环境影响
采购公司将来可能会产生因供应商的二氧化碳排放，违反安全规定或其他社会或环境影响有关的成本。了解供应商的影响需要付出昂贵的努力，但有必要（有时甚至必须）来减少这些影响。采购公司的资本市场估值反映了投资者对与供应商影响有关的未来成本的估计，以及采购公司为了解和减少供应商影响而产生的任何成本。本文分析了一种博弈论模型，其中经理（目的是使采购公司的资本市场价值最大化）决定是否了解供应商的影响，为减轻供应商的影响而付出的成本以及是否披露供应商对投资者的影响。投资者有合理的预期（例如，经理可能隐瞒有关供应商影响的坏消息）并据此对购买公司进行估值。本文考虑了公开披露有关供应商影响信息的授权，并表明，披露要求阻碍了对供应商的了解，因此，在合理的条件下，会导致更高的预期影响。仅当采购公司面对与供应商影响相关的未来成本较高时，披露要求才能导致较低的预期影响。相比之下，披露要求总是会增加采购公司预期的折现利润和资本市场估值。披露要求可以促使采购公司与分享信息的供应商进行合作，但会导致供应商产生更高的预期影响。当采购公司有替代供应商时，披露要求倾向于对供应商的承诺，以促进了解该供应商的影响（而不是寻找影响较小的供应商）。
A buying firm might in the future incur costs associated with a supplier’s carbon dioxide emissions, safety violations, or other social or environmental impacts. Learning about a supplier’s impacts requires costly effort, but it is necessary (and sometimes sufficient) to reduce those impacts. The capital market valuation of a buying firm reflects investors’ estimate of future costs associated with a supplier’s impacts, as well as any costs that the buying firm incurs in order to learn about and reduce a supplier’s impacts. This paper analyzes a game theoretic model in which a manager—with the objective of maximizing the capital market valuation of the buying firm—decides whether to learn about a supplier’s impacts, how much cost to incur to reduce the supplier’s impacts, and whether to disclose the supplier’s impacts to investors. The investors have rational expectations (e.g., that a manager might withhold bad news about the supplier’s impacts) and value the buying firm accordingly. The paper considers a mandate to disclose information learned about a supplier’s impacts. The paper shows that the disclosure mandate deters learning and thus, under plausible conditions, results in higher expected impacts. The disclosure mandate can result in lower expected impacts only if buying firms face moderately high future costs associated with suppliers’ impacts. In contrast, a disclosure mandate always increases a buying firm’s expected discounted profit and capital market valuation. A disclosure mandate can induce cooperation among buying firms with a shared supplier, yet result in higher expected impacts by the supplier. When a buying firm has alternative suppliers, the disclosure mandate favors commitment to a supplier to facilitate learning about that supplier’s impacts (instead of searching for a lower-impact supplier).
参考文献：Kalkanci, B., & Plambeck, E. L. (2020). Managing Supplier Social and Environmental Impacts with Voluntary Versus Mandatory Disclosure to Investors. Management Science.
3. 使用RSOME轻松进行强大的随机优化
本文提出了一种称为鲁棒随机优化（RSO）的新的分布式鲁棒优化模型，该模型在可行的框架内将基于场景树的随机线性优化和分布式鲁棒优化相结合，可以使用最新的商业优化计算器来解决。本文还开发了一个新的代数建模程序包，即“易于实现的鲁棒随机优化”（RSOME），以促进RSO模型的实现。不确定性模型同时包含离散变量和连续随机变量，通常分别假设在基于场景树的随机线性优化和分布稳健性优化中。为了解决资源决定决策的非预期性，本文介绍了事件智能资源自适应，它整合了源自随机线性优化的场景树自适应和在分布鲁棒优化中流行的仿射自适应。本文提出的事件智能模糊集足够丰富，可以捕获具有凸广义矩，混合分布，φ-散度，Wasserstein（Kantorovich-Rubinstein）度量的传统的基于统计的模糊集，并且还可以使用诸如K-means聚类，分类和回归树的技术启发基于机器学习的模糊集。提供了一些有趣的RSO模型，包括根据Hurwicz准则进行优化以及针对Wasserstein模糊度集的两阶段问题。
We present a new distributionally robust optimization model called robust stochastic optimization (RSO), which unifies both scenario-tree-based stochastic linear optimization and distributionally robust optimization in a practicable framework that can be solved using the state-of-the-art commercial optimization solvers. We also develop a new algebraic modeling package, Robust Stochastic Optimization Made Easy (RSOME), to facilitate the implementation of RSO models. The model of uncertainty incorporates both discrete and continuous random variables, typically assumed in scenario-tree-based stochastic linear optimization and distributionally robust optimization, respectively. To address the nonanticipativity of recourse decisions, we introduce the event-wise recourse adaptations, which integrate the scenario-tree adaptation originating from stochastic linear optimization and the affine adaptation popularized in distributionally robust optimization. Our proposed event-wise ambiguity set is rich enough to capture traditional statistic-based ambiguity sets with convex generalized moments, mixture distribution, φ-divergence, Wasserstein (Kantorovich-Rubinstein) metric, and also inspire machine-learning-based ones using techniques such as K-means clustering and classification and regression trees. Several interesting RSO models, including optimizing over the Hurwicz criterion and two-stage problems over Wasserstein ambiguity sets, are provided.
参考文献：Chen, Z., Sim, M., & Xiong, P. (2020). Robust stochastic optimization made easy with rsome. Management Science.
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4. 差旅费用如何影响合作？
本文开发了一个简单的理论框架，用于考虑地理摩擦（尤其是差旅费用）如何影响科学家的合作决策以及本地开发或远距离开发的项目类型。然后，本文利用准实验（即低成本航空公司引入的新航线）的优势来检验该理论的预测。结果表明，差旅费用构成了合作的重要摩擦：低成本航空公司进入后，合作次数增加了0.3到1.1倍，这一结果对于多种虚拟测试和因果关系均十分可靠。地理摩擦的减少对于原本在本地环境更恶劣的高素质科学家尤其有利。与该理论一致，较低的差旅费用也内生性地改变了科学家在不同距离水平上从事的项目类型。引进后，本文观察到高质量和新颖项目的增加，以及利用子领域之间互补的知识和技能并依靠专用设备的项目。本文测试了从化学到广泛学科的科学出版物数据以及不同领域（专用设备不太可能与数学相关）的发现的可概括性。最后，本文讨论了远距离组建协作研发团队的意义。
We develop a simple theoretical framework for thinking about how geographic frictions, and in particular travel costs, shape scientists’ collaboration decisions and the types of projects that are developed locally versus over distance. We then take advantage of a quasi-experiment—the introduction of new routes by a low-cost airline—to test the predictions of the theory. Results show that travel costs constitute an important friction to collaboration: after a low-cost airline enters, the number of collaborations increases between 0.3 and 1.1 times, a result that is robust to multiple falsification tests and causal in nature. The reduction in geographic frictions is particularly beneficial for high-quality scientists that are otherwise embedded in worse local environments. Consistent with the theory, lower travel costs also endogenously change the types of projects scientists engage in at different levels of distance. After the shock, we observe an increase in higher-quality and novel projects, as well as projects that take advantage of complementary knowledge and skills between subfields, and that rely on specialized equipment. We test the generalizability of our findings from chemistry to a broader data set of scientific publications and to a different field where specialized equipment is less likely to be relevant, mathematics. Last, we discuss implications for the formation of collaborative research and development teams over distance.
参考文献：Catalini, C., Fons-Rosen, C., & Gaulé, P. (2020). How Do Travel Costs Shape Collaboration?. Management Science.
5. 董事网络是否对财务报告质量很重要？审计委员会关联性和再声明的证据
这项研究考察了通过董事网络建立的审计委员会的连通性对财务报告质量的影响，特别是对年度财务报表的错报。使用网络分析，本文检查了连通性的多个维度，并发现在控制运营绩效和公司治理特征之后，拥有紧密联系的审计委员会的公司不太可能错误陈述年度财务报表。此外，本文的研究表明，审计委员会通过董事网络的联系减少了董事会联盟对财务报告质量不佳的公司的负面影响。本文进行了一些测试来解决识别问题并找到相似的结果。本文的发现表明，审计委员会之间的联系更加紧密的公司不太可能采用降低财务报告质量的报告做法。
This study examines the effect of audit committee connectedness through director networks on financial reporting quality, specifically the misstatement of annual financial statements. Using network analysis, we examine multiple dimensions of connectedness and find that after controlling for operating performance and corporate governance characteristics, firms with well-connected audit committees are less likely to misstate annual financial statements. In addition, our study demonstrates that audit committee connectedness through director networks moderates the negative effect of board interlocks to misstating firms on financial reporting quality. We conduct several tests to address identification concerns and find similar results. Our findings suggest that firms with better-connected audit committees are less likely to adopt reporting practices that reduce financial reporting quality.
参考文献：Omer, T. C., Shelley, M. K., & Tice, F. M. (2020). Do director networks matter for financial reporting quality? Evidence from audit committee connectedness and restatements. Management Science, 66(8), 3361-3388.
6. 普通审计市场的监管溢出效应
本文发现萨班斯-奥克斯利法案（SOX）对非公共实体的审计市场有两个重要影响。最初的短期影响源于劳动力供应缺乏弹性，再加上上市公司的审计需求冲击。结果，私人公司将其在银行融资中使用经证明的财务报告的比例减少了12％，并且非营利组织（NPO）的审计费增加了两倍多。第二个长期影响是审计供应结构的转变。在SOX之后，非营利组织不太可能与最受公众公司欢迎的审计师相匹配，而审计师则越来越根据客户类型对其办事处进行专门化。在SOX执行的五年内，非营利组织的审计市场集中度下降了一半以上，并且到2013年样本结束时一直保持在这一水平，而供应商数量却增长了26％。本文的结果表明，针对上市公司的监管如何对非上市实体产生重要的经济溢出效应。
We find that Sarbanes–Oxley (SOX) had two significant effects on the audit market for nonpublic entities. The first short-run effect stems from inelastic labor supply coupled with an audit demand shock from public companies. As a result, private companies reduced their use of attested financial reports in bank financing by 12%, and audit fee increases for nonprofit organizations (NPOs) more than doubled. The second long-run effect was a transformation in the audit supply structure. After SOX, NPOs were less likely to match with auditors most exposed to public companies, whereas auditors increasingly specialized their offices based on client type. Audit market concentration for NPOs dropped by more than one-half within five years of SOX and remained at this level through the end of our sample in 2013, whereas the number of suppliers increased by 26%. Our results demonstrate how regulation directed at public companies generates economically important spillovers for nonpublic entities.
参考文献：Duguay, R., Minnis, M., & Sutherland, A. (2020). Regulatory spillovers in common audit markets. Management Science, 66(8), 3389-3411.
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7. 有效评估目标政策：改进“冠军与挑战者”实验
冠军与挑战者的田野实验被广泛用于比较不同目标策略的效果。这些实验会随机分配客户以接受现有（冠军）政策或新（挑战者）政策建议的营销活动，然后比较汇总结果。本文建议采用替代性实验设计，并提出替代性评估方法，以改善针对性定位政策的评估。推荐的实验设计会随机分配客户进行营销活动。这样就可以评估任何定位策略，而无需进行其他实验，包括在实施实验后设计的策略。拟议的估算方法确定了针对不同策略建议采取相同操作的客户，并认识到这些客户的绩效没有差异。这样可以更精确地比较策略。本文使用来自实际现场实验的数据说明了实验设计和估算方法的优势。本文还证明，作为本文估算方法基础的客户分组可以帮助改善对新定位策略的培训。
Champion versus challenger field experiments are widely used to compare the performance of different targeting policies. These experiments randomly assign customers to receive marketing actions recommended by either the existing (champion) policy or the new (challenger) policy, and then compare the aggregate outcomes. We recommend an alternative experimental design and propose an alternative estimation approach to improve the evaluation of targeting policies. The recommended experimental design randomly assigns customers to marketing actions. This allows evaluation of any targeting policy without requiring an additional experiment, including policies designed after the experiment is implemented. The proposed estimation approach identifies customers for whom different policies recommend the same action and recognizes that for these customers there is no difference in performance. This allows for a more precise comparison of the policies. We illustrate the advantages of the experimental design and estimation approach using data from an actual field experiment. We also demonstrate that the grouping of customers, which is the foundation of our estimation approach, can help to improve the training of new targeting policies.
参考文献：Simester, D., Timoshenko, A., & Zoumpoulis, S. I. (2020). Efficiently Evaluating Targeting Policies: Improving on Champion vs. Challenger Experiments. Management Science.
8. 桥接学术界和工业界：地理中心如何连接大学科学和公司技术
创新型公司越来越依赖于学术科学，但它们仅利用所有学术发现中的一小部分。公司在学术上有哪些发现？本文假设中心在学术科学和公司技术之间起着桥梁的作用。从专利到大约一千万篇学术文章的引用，本文发现枢纽以两种方式促进学术科学向公司发明的流动。首先，学术界基于枢纽的发现具有更高的质量和更多的应用。第二，公司，尤其是年轻的，创新的，以科学为导向的公司，对基于中心的发现的关注过多。本文通过在147个同时发现的集合中确认公司对基于中心的科学的关注，来解决有关未观察到的异质性的问题。重要的是，枢纽不仅促进了本地化的知识流动，而且扩展了学术科学的地理范围，吸引了远方公司的注意力。
Innovative firms rely increasingly on academic science, yet they exploit only a small fraction of all academic discoveries. Which discoveries in academia do firms build upon? We posit that hubs play the role of bridges between academic science and corporate technology. Tracking citations from patents to approximately 10 million academic articles, we find that hubs facilitate the flow of academic science into corporate inventions in two ways. First, hub-based discoveries in academia are of higher quality and are more applied. Second, firms—in particular young, innovative, science-oriented ones—pay disproportionate attention to hub-based discoveries. We address concerns regarding unobserved heterogeneity by confirming the role of firms’ attention to hub-based science in a set of 147 simultaneous discoveries. Importantly, hubs not only facilitate localized knowledge flow but also extend the geographic reach of academic science, attracting the attention of distant firms.
参考文献：Bikard, M., & Marx, M. (2020). Bridging academia and industry: How geographic hubs connect university science and corporate technology. Management Science, 66(8), 3425-3443.
9. 抵消分歧和证券价格
本文认为投资者的信念经常“交叉”，即投资者可能喜欢公司A但不喜欢公司B，而另一位投资者可能喜欢公司B但不喜欢公司A。这种信念交叉使得构建仅由每个投资者最喜欢的公司组成的投资组合几乎是不可能的。这导致投资组合的兴奋程度通常低于单个公司在其最热情的支持者中产生的兴奋程度。再加上卖空限制，其中最乐观的投资者确定价格，这导致投资组合以折扣价交易。通过使用几种设置，可以分别评估投资组合的价值和基础组成部分的价值（例如，封闭式基金），本文提供了支持本文的主张的证据，即在金融市场中，“整体”通常小于“其各部分之和”。
We propose that investor beliefs frequently “cross” in the sense that an investor may like company A but dislike company B, whereas another investor may like company B but dislike company A. Such belief-crossing makes it almost impossible to construct a portfolio that is composed solely of every investor’s most favored companies. This causes the level of excitement for portfolios to be generally lower than the levels of excitement that individual companies generate among their most fervent supporters. Coupled with short-sale constraints, wherein prices are set by the most optimistic investors, this causes portfolios to trade at discounts. Utilizing several settings whereby the value of a portfolio and the values of the underlying components can be evaluated separately (e.g., closed-end funds), we present evidence supporting our proposition that, in financial markets, the “whole” is often less than the “sum of its parts.”
参考文献：Huang, S., Hwang, B. H., Lou, D., & Yin, C. (2020). Offsetting disagreement and security prices. Management Science.
10. 零
资产价格可能会过时。本文将价格陈旧性定义为缺乏价格调整产生了零回报（即“零”）。相反，“闲置”（接近闲置）用于定义当交易活动不存在（几乎不存在）时的陈旧性。使用统计和定价指标，本文表明“零”是与交易量以及因此流动性动态相关的真实经济现象。总的来说，“零”不是制度特征（例如价格离散）的结果。从本质上讲，闲置或接近闲置的现象是风格化的事实，暗示着资产价格建模中关键的，被忽略的市场摩擦。本文说明了考虑这种摩擦如何在短期期权收益中产生可观的风险补偿的。
Asset prices can be stale. We define price staleness as a lack of price adjustments yielding zero returns (i.e., zeros). The term idleness (respectively, near idleness) is, instead, used to define staleness when trading activity is absent (respectively, close to absent). Using statistical and pricing metrics, we show that zeros are a genuine economic phenomenon linked to the dynamics of trading volume and, therefore, liquidity. Zeros are, in general, not the result of institutional features, like price discreteness. In essence, spells of idleness or near idleness are stylized facts suggestive of a key, omitted market friction in the modeling of asset prices. We illustrate how accounting for this friction may generate sizable risk compensations in short-dated option returns.
参考文献：Bandi, F. M., Kolokolov, A., Pirino, D., & Renò, R. (2020). Zeros. Management Science.
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11. 时间依赖性患者不出现行为下的预约安排
本文研究如何安排存在时间依赖性患者不出现行为和随机服务时间的医疗预约问题。该问题来自于本文对来自两个大洲的国家的独立数据集的研究，这些数据均确定了一天中患者出现概率的重大影响。本文构建了一个分布鲁棒模型，通过优化患者的计划到达时间，该模型将最坏情况下的患者等待总预期花费以及服务医生的空闲和加班时间降到最低。该模型具有挑战性，因为评估给定调度方案的总成本涉及一个线性规划，该线性规划在目标函数和约束右侧都存在不确定性。另外，所考虑的模糊集包含离散的不确定性和这些不确定性之间的互补功能关系（即，患者未出现和服务时间）。本文表明，当患者的缺席诊治是外生性的（即与时间无关）时，可以将该问题重新表述为一个正定程序，然后通过半定规划进行近似。当患者的缺席时间是内生的（按照时间安排）时，问题就变成了双线性共正程序。本文构造了一套双重定价，以寻找合适的调度方案，并反复使用该技术来获得接近最佳的解决方案。本文的计算表明，考虑患者出现时间概率的每日变化而不是忽略它，可以大大降低总预期成本。
This paper studies how to schedule medical appointments with time-dependent patient no-show behavior and random service times. The problem is motivated by our studies of independent datasets from countries in two continents that unanimously identify a significant time-of-day effect on patient show-up probabilities. We deploy a distributionally robust model, which minimizes the worst-case total expected costs of patient waiting and service provider’s idling and overtime, by optimizing the scheduled arrival times of patients. This model is challenging because evaluating the total cost for a given schedule involves a linear program with uncertainties present in both the objective function and the right-hand side of the constraints. In addition, the ambiguity set considered contains discrete uncertainties and complementary functional relationships among these uncertainties (namely, patient no-shows and service durations). We show that when patient no-shows are exogenous (i.e., time-independent), the problem can be reformulated as a copositive program and then be approximated by semidefinite programs. When patient no-shows are endogenous on time (and hence on the schedule), the problem becomes a bilinear copositive program. We construct a set of dual prices to guide the search for a good schedule and use the technique iteratively to obtain a near-optimal solution. Our computational studies reveal a significant reduction in total expected cost by taking into account the time-of-day variation in patient show-up probabilities as opposed to ignoring it.
参考文献：Kong, Q., Li, S., Liu, N., Teo, C. P., & Yan, Z. (2020). Appointment scheduling under time-dependent patient no-show behavior. Management Science.
12. 并行单服务器队列系统的受约束的负载平衡策略
平衡服务器负载的流控制策略，以提高多节点排队系统的性能而闻名。尽管负载平衡使整个系统受益，但它可能会对某些排队节点产生负面影响。例如，就某些性能指标而言，它可能会降低吞吐率或导致不公平。对于具有多个单服务器节点的排队系统，本文提出了一组受约束的负载平衡策略，以确保不会减少到达每个排队节点的预期到达率，并且本文证明了这些策略为每个排队节点提供了多种好处：随机地减少客户和每个排队节点上客户数量的方差。这些结果表明，通过多个通用目标函数衡量的性能提高，包括但不限于排队节点上的预期客户数量，拥有大量客户的概率，客户数量的方差以及有条件的预期客户数量超过固定服务级别的阈值。本文从数据结果上证明了提出的政策可以挖掘出很大一部分潜在的改进。
Flow-control policies that balance server loads are well known for improving performance of queueing systems with multiple nodes. However, although load balancing benefits the system overall, it may negatively impact some of the queueing nodes. For example, it may reduce throughput rates or engender unfairness with respect to some performance measures. For queueing systems with multiple single-server nodes, we propose a set of constrained load-balancing policies that ensures the expected arrival rate to each queueing node is not reduced, and we show that such policies provide multiple benefits for each queueing node: stochastically fewer customers and lower variance of the number of customers at each queueing node. These results imply performance improvement as measured by multiple general objective functions, including but not limited to the expected number of customers at a queueing node, probability of having a high number of customers, variance of the number of customers, and expected number of customers conditional on exceeding a threshold defined by a fixed service level. We demonstrate numerically that our proposed policies capture a large portion of the potential maximal improvement.
参考文献：Do, H. T., & Shunko, M. (2020). Constrained Load-Balancing Policies for Parallel Single-Server Queue Systems. Management Science.
13. 重新设计志愿者市场：捐赠者注册处
本文针对的是志愿劳动力市场，在这些市场中，缺乏价格信号、非金钱动机的劳动力供应以及有限的供应替代性，导致市场失灵。为了解决市场失灵的原因，本文与自愿全血供者进行了实地实验，引入了市场清理机制（以下简称注册处）。本文的处理意向估计值表明，邀请参加注册的对象（无论是否加入）对严重短缺呼吁的响应比对照对象高66％。虽然注册处在严重短缺期间增加了供应，但在没有短缺时却没有增加供应；因此，注册处大大改善了志愿捐助者与人才资源中心之间的协调，从而改善了市场供应。本文发现有证据表明，注册处的效力源于纯粹出于利他动机的志愿者和偏爱承诺的志愿者。
This paper addresses volunteer labor markets where the lack of price signals, nonpecuniary motivations to supply labor, and limited fungibility of supply lead to market failure. To address the causes of the market failure, we conduct a field experiment with volunteer whole blood donors where we introduce a market-clearing mechanism (henceforth: the Registry). Our intention-to-treat estimates suggest that subjects invited to the Registry, regardless of joining, are 66% more responsive to critical shortage appeals than control subjects. While the Registry increases supply during a critical shortage episode, it does not increase supply when there is no shortage; thus, the Registry significantly improves coordination between volunteer donors and collection centers, thereby improving market outcomes. We find evidence that the Registry’s effectiveness stems from crowding-in volunteers with purely altruistic motives and volunteers with a preference for commitment.
参考文献：Heger, S. A., Slonim, R., Garbarino, E., Wang, C., & Waller, D. (2020). Redesigning the Market for Volunteers: A Donor Registry. Management Science.
14. 市场时机对股东有利吗？
公司经常交易自己定价有误的股票。这种称为股票市场时机（market timing）的活动可以产生可观的利润并提高长期股价。本文质疑与此密切相关的一个流行观点，即市场时机总是使公司股东受益。由于逆向选择和公司短期价格的变化，公司的机会性融资策略可能会对不知情的股票持有人产生负面影响，而长期收益不会累积给即将退出的股东。市场时机对股东的负面影响随着股票交易量的增加而增加。此外，时间安排的影响是不对称的：股东更愿意公司纠正定价偏低而不是定价偏高。本文的理论可以更好地解释观察到的公司股票发行和回购活动。
Corporations often transact in their own mispriced stock. This activity, known as equity market timing, can generate substantial profits and increase the long-term stock price. We challenge a closely related popular view that market timing always benefits firm shareholders. Opportunistic financing maneuvers by a firm can negatively affect its uninformed stock owners because of adverse selection and the change in the firm’s short-term price, whereas the long-term returns do not accumulate to departing stockholders. The negative effect of market timing on stockholders increases with the share turnover. Furthermore, the effect of timing is asymmetric: shareholders prefer that the firm corrects underpricing rather than overpricing. Our theory can be used to better interpret the observed stock issuance and repurchase activities of firms.
参考文献：Babenko, I., Tserlukevich, Y., & Wan, P. (2020). Is market timing good for shareholders?. Management Science.
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15. 众筹，融资约束和实际效果
本文研究了预售众筹合同的可行性和最佳设计，其中参与的消费者支付的价格高于未来预期现货价格的溢价，并且受财务约束的企业家在通过预售众筹引入的潜在产品-市场扭曲与传统外部融资成本之间取得了平衡。本文的分析表明，这种众筹合同如何使原本无法进行的项目得以执行，并创新地强调了资本成本，需求不确定性和生产之间的相互作用。严格的融资限制降低了垄断者获得剩余的能力，但与通常的结果相反，可能会增加产量。本文评估不确定性和市场规模如何降低垄断者的价格歧视能力并影响最佳合同制度。然而，本文展示了即使在潜在消费者数量相对较高且他们的个人需求是随机的情况下，这种预售价格区分性合同也是可以并如何实施的。
We study the feasibility and optimal design of presale crowdfunding contracts where participating consumers pay a premium above the future expected spot price and financially constrained entrepreneurs balance the potential product–market distortions introduced through presale crowdfunding against the cost of traditional external financing. Our analysis shows how such crowdfunding contracts enable the execution of projects that could not be otherwise undertaken and highlights novel interactions between the cost of capital, demand uncertainty, and production. Tighter financing constraints reduce the ability of the monopolist to extract surplus but, contrary to the usual result, may increase production. We evaluate how uncertainty and market size reduce the price-discriminating power of the monopolist and affect the optimal contract regime. Nevertheless, we show how such presale price-discriminating contracts are implementable even when the number of potential consumers is relatively high and their individual demand is stochastic.
参考文献：Kumar, P., Langberg, N., & Zvilichovsky, D. (2020). Crowdfunding, Financing Constraints, and Real Effects. Management Science, 66(8), 3561-3580.
16. 互惠基金的浮动定价：打破“火灾销售”和基金赎回之间的反馈循环
本文建立了共同基金流出与资产流动性之间的反馈模型。市场震荡后，精明的投资者预计其他投资者的赎回将对基金的资产净值（NAV）产生影响，并先以有利的价格退出。先发制人的优势可能会导致价格下跌和赎回增加的循环而导致资金失败。本文的分析表明：（i）先行优势在市场冲击与赎回对基金净资产值的总体影响之间引入了非线性依赖性；（ii）结果是，冲击的严重程度超过了赎回额，导致资金下降；（iii）设计合理的浮动定价将清算成本从基金转移到了赎回投资者，并且通过消除先发优势带来的非线性降低成本并防止基金倒闭。要实现这些目标，就需要在更大的流出水平上有更大的波动系数。一个基金的波动因素也可能取决于其他基金所遵循的政策。
We develop a model of the feedback between mutual fund outflows and asset illiquidity. Following a market shock, alert investors anticipate the impact on a fund’s net asset value (NAV) of other investors’ redemptions and exit first at favorable prices. This first-mover advantage may lead to fund failure through a cycle of falling prices and increasing redemptions. Our analysis shows that (i) the first-mover advantage introduces a nonlinear dependence between a market shock and the aggregate impact of redemptions on the fund’s NAV; (ii) as a consequence, there is a critical magnitude of the shock beyond which redemptions brings down the fund; (iii) properly designed swing pricing transfers liquidation costs from the fund to redeeming investors and, by removing the nonlinearity stemming from the first-mover advantage, it reduces these costs and prevents fund failure. Achieving these objectives requires a larger swing factor at larger levels of outflows. The swing factor for one fund may also depend on policies followed by other funds.
参考文献：Capponi, A., Glasserman, P., & Weber, M. (2020). Swing pricing for mutual funds: Breaking the feedback loop between fire sales and fund redemptions. Management Science.
17. 衍生品市场的蔓延
重大的信贷冲击可能会导致衍生品市场交易对手之间的日间较大幅度的保证金支付，这可能会迫使一些参与者拖欠其付款。随着支付风险通过风险网络的级联，这些支付不足的情况变得越来越严重。使用美国存托凭证和清算公司的详细数据，本文对在美国信用违约掉期市场中运营的约900家公司的风险敞口，激进支付，初始保证金以及流动性缓冲的完整网络进行建模。本文估算了危机蔓延的总量，每家企业对危机蔓延的边际贡献以及因信贷利差而受到系统性冲击的违约企业的数量。该模型的一个新颖特征是，它允许对资产负债表压力进行一系列行为响应，包括延迟或部分还款。该模型提供了一个框架，用于分析不同政策选择的相对有效性，例如增加保证金要求或强制增加流动性储备。
A major credit shock can induce large intraday variation margin payments between counterparties in derivatives markets, which may force some participants to default on their payments. These payment shortfalls become amplified as they cascade through the network of exposures. Using detailed Depository Trust & Clearing Corporation data, we model the full network of exposures, shock-induced payments, initial margin collected, and liquidity buffers for about 900 firms operating in the U.S. credit default swaps market. We estimate the total amount of contagion, the marginal contribution of each firm to contagion, and the number of defaulting firms for a systemic shock to credit spreads. A novel feature of the model is that it allows for a range of behavioral responses to balance sheet stress, including delayed or partial payments. The model provides a framework for analyzing the relative effectiveness of different policy options, such as increasing margin requirements or mandating greater liquidity reserves.
参考文献：Paddrik, M., Rajan, S., & Young, H. P. (2020). Contagion in derivatives markets. Management Science.
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18. 在线市场的排名和拍卖
亚马逊和淘宝等在线电子商务平台每天连接成千上万的卖家和消费者。在这项工作中，本文研究了此类平台应如何对展示给消费者的产品进行排名，并利用最重要的广告位。本文提出了一个模型，该模型考虑了消费者的搜索成本和卖方相互施压的外部性。该模型使本文能够研究多目标优化，其目标包括消费者和卖方剩余以及销售收入，并得出最佳排名决策。此外，本文提出了一种盈余排序的排名机制，用于出售一些排名靠前的广告位。该机制部分是由亚马逊赞助的搜索程序推动的。本文证明了维克瑞-克拉克-格罗夫斯机制不适用于本文的环境，并提出了一种新的机制。这种机制几乎是最佳的，其表现要明显好于那些不鼓励卖方透露有关每个消费者购买的私人信息（例如利润）的机制。此外，本文将模型推广到各种设置中，在这些设置中，平台可以提供有关产品的部分信息并方便消费者搜索，显示了本文发现的可靠性。
Online e-commerce platforms, such as Amazon and Taobao, connect thousands of sellers and consumers every day. In this work, we study how such platforms should rank products displayed to consumers and utilize the top and most salient slots. We present a model that considers consumers’ search costs and the externalities sellers impose on each other. This model allows us to study a multiobjective optimization, whose objective includes consumer and seller surplus as well as the sales revenue, and derive the optimal ranking decision. In addition, we propose a surplus-ordered ranking mechanism for selling some of the top slots. This mechanism is motivated in part by Amazon’s sponsored search program. We show that the Vickrey–Clarke–Groves mechanism would not be applicable to our setting and propose a new mechanism. This mechanism is near optimal, performing significantly better than those that do not incentivize sellers to reveal their private information regarding each consumer purchase, such as their profit. Moreover, we generalize our model to settings in which platforms can provide partial information about the products and facilitate the consumer search and show the robustness of our findings.
参考文献：Chu, L. Y., Nazerzadeh, H., & Zhang, H. (2020). Position ranking and auctions for online marketplaces. Management Science.
19. 混合分布的非参数估计的条件梯度法
混合估计模型是通用工具，已广泛应用于许多领域，包括运营，市场营销和计量经济学。混合估计模型的主要挑战是混合分布通常是未知的，而施加先验参数假设可能会导致模型规格不正确的问题。在本文中，本文提出了一种用于非参数估计logit模型混合分布的新方法。本文将基于似然的估计问题公式化为约束凸程序，并应用条件梯度（也称为Frank-Wolfe）算法来解决该凸程序。本文表明，本文的方法迭代生成了混合分布和混合比例。从理论上讲，本文建立了估计器的亚线性收敛速度，并描述了恢复混合分布的结构。根据经验，本文在真实数据集上测试本文的方法。本文证明它在速度（快16倍），样本拟合（对数似然损失最多减少24％）和预测性（平均标准误差平均减少28％）方面都优于标准的预期最大化（EM）基准指标）和决策准确性（提取的结果大约增加了23％）。在综合数据上，本文表明本文的估计器对于不同的地面真相混合分布具有鲁棒性，并且还可以解释内生性。
Mixture models are versatile tools that are used extensively in many fields, including operations, marketing, and econometrics. The main challenge in estimating mixture models is that the mixing distribution is often unknown, and imposing a priori parametric assumptions can lead to model misspecification issues. In this paper, we propose a new methodology for nonparametric estimation of the mixing distribution of a mixture of logit models. We formulate the likelihood-based estimation problem as a constrained convex program and apply the conditional gradient (also known as Frank–Wolfe) algorithm to solve this convex program. We show that our method iteratively generates the support of the mixing distribution and the mixing proportions. Theoretically, we establish the sublinear convergence rate of our estimator and characterize the structure of the recovered mixing distribution. Empirically, we test our approach on real-world datasets. We show that it outperforms the standard expectation-maximization (EM) benchmark on speed (16 times faster), in-sample fit (up to 24% reduction in the log-likelihood loss), and predictive (average 28% reduction in standard error metrics) and decision accuracies (extracts around 23% more revenue). On synthetic data, we show that our estimator is robust to different ground-truth mixing distributions and can also account for endogeneity.
参考文献：Jagabathula, S., Subramanian, L., & Venkataraman, A. (2020). A conditional gradient approach for nonparametric estimation of mixing distributions. Management Science.
20. 优化择校问题中的分配目标
我研究了学校选择的三个目标：福利，鼓励邻里学校和多元化。我使用优化问题来为这些目标的任何组合找到最佳的稳定性和激励相容性匹配。这些问题假定学生和学校席位是连续的，这使我能够以易处理的形式描述激励相容性条件。我证明了稳定匹配的集合在学生分布和学校能力方面通常是连续的，这意味着连续模型中可能的稳定匹配的特征近似于具有较大匹配市场的匹配市场中的稳定匹配集合。学生人数有限。然后，我将我的框架应用于来自波士顿公立学校的数据。如果该机制以人口统计学为条件，则学生福利的改善（相对于现状）相当于将291名学生（3479名学生中）移至其偏好列表中排名更高的学校。相反，如果该机制不以人口统计学为条件，那么福利的改善等同于仅将25.1名学生上移一级。可以在不降低福利或多样性的情况下改善分配目标（例如，将邻里学校的入学率提高50％）。
I investigate three goals of school choice: welfare, encouraging neighborhood schools, and diversity. I use optimization problems to find the best stable and incentive compatible match for any combination of these objectives. These problems assume there is a continuum of students and school seats, which allows me to describe the incentive compatibility conditions in a tractable form. I prove that the set of stable matchings is generically continuous in the distribution of students and the school capacities, which implies that the characterization of the possible stable matches in the continuum model approximates the set of stable matches in a matching market with a large, but finite, number of students. I then apply my framework to data from Boston Public Schools. If the mechanism conditions on demographics, the improvement (relative to the status quo) in student welfare is equivalent to moving 291 students (out of 3,479) to schools one rank higher in their preference lists. In contrast, if the mechanism does not condition on demographics, the welfare improvement is equivalent to moving only 25.1 students to schools one rank higher. Improvements in the distributional goals can be made (e.g., increasing enrollment in neighborhood schools by 50%) without reducing welfare or diversity.
参考文献：Bodoh-Creed, A. L. (2020). Optimizing for distributional goals in school choice problems. Management Science.
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21. 星期五效应：公司游说，药物安全警报的时间安排和药物副作用
安全警报是由健康监管机构发布的警告，警告患者和医生有关新药物的副作用。但是，并非所有安全警报都同样有效。本文提供的证据表明，发布安全警报的星期几可以解释安全警报影响的差异。具体而言，本文显示，周五发布的安全警报的传播范围较广：在社交媒体上的安全警报共享减少了34％，新闻文章中提及的安全警报减少了23％至66％，新闻接收的可能性降低了12％至51％ 完全没有 因此，本文建议星期五警报在减少与毒品有关的副作用方面不太有效。本文发现，将星期五警报转移到任何其他工作日将使所有与毒品有关的副作用减少9％至12％，将与毒品有关的严重并发症减少6％至15％，并将与毒品有关的死亡减少22％至36％。这个问题尤为重要，因为星期五是1999年至2016年间安全警报公告最频繁的工作日。本文证明，星期五警报的这种流行程度可能不是随机的：过去游说过美国食品药品监督管理局的公司占49％ 周五宣布安全警报的可能性提高了56％。
Safety alerts are announcements made by health regulators warning patients and doctors about new drug-related side effects. However, not all safety alerts are equally effective. We provide evidence that the day of the week on which the safety alerts are announced explains differences in safety alert impact. Specifically, we show that safety alerts announced on Fridays are less broadly diffused: they are shared 34% less on social media, mentioned in 23% to 66% fewer news articles, and are 12% to 51% less likely to receive any news coverage at all. As a consequence of this, we propose Friday alerts are less effective in reducing drug-related side effects. We find that moving a Friday alert to any other weekday would reduce all drug-related side effects by 9% to 12%, serious drug-related complications by 6% to 15%, and drug-related deaths by 22% to 36%. This problem is particularly important because Friday was the most frequent weekday for safety alert announcements from 1999 to 2016. We show that this greater prevalence of Friday alerts might not be random: firms that lobbied the U.S. Food and Drug Administration in the past are 49% to 56% more likely to have safety alerts announced on Fridays.
