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Recharging Retail: Estimating Consumer Demand Spillovers from Electric Vehicle Charging Stations 充电零售:估算电动汽车充电站对消费者需求的溢出效应
Pub Date : 2024-02-12 DOI: 10.1287/msom.2022.0519
Yash Babar, Gordon Burtch
Problem definition: We estimate the impact of electric vehicle (EV) charging stations on volumes of consumer foot traffic received by nearby retail establishments. We also explore the conditions under which any effects manifest. Methodology/results: We use a differences-in-differences design, exploiting the staggered introduction of Tesla Supercharger stations across the United States. We combine data on Supercharger installations with mobile phone–based estimates of retailer foot traffic. We explore heterogeneity in the treatment effect, in terms of EV charger characteristics, visitor characteristics, establishment type, and local physical context. We estimate that establishments experience an average 4% increase in monthly visits following the installation of a Tesla Supercharger. These effects arise primarily for retailers that offer relatively quick services (e.g., fast food) and for those located very near to the charger (within 150 meters). The effects are also more pronounced when the Supercharger is one of the first EV chargers introduced into the local area. Managerial implications: We document evidence of the positive retail demand spillovers arising from EV charging station infrastructure. We also document the conditions under which the benefits manifest. Insights for EV network operators, retailers, and policymakers are included.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0519 .
问题定义:我们估算了电动汽车(EV)充电站对附近零售店消费者人流量的影响。我们还探讨了在哪些条件下会产生影响。方法/结果:我们采用差异设计,利用特斯拉超级充电站在全美的交错引入。我们将超级充电站的安装数据与基于手机的零售商人流量估算相结合。我们从电动汽车充电器特征、游客特征、机构类型和当地自然环境等方面探讨了治疗效果的异质性。我们估计,在安装特斯拉超级充电器后,商店的月访问量平均增加了 4%。这些效应主要产生于提供相对快捷服务的零售商(如快餐店)和距离充电器非常近(150 米内)的零售商。当超级充电器是当地最早引入的电动汽车充电器之一时,这种效应也会更加明显。管理意义:我们记录了电动汽车充电站基础设施带来的积极零售需求溢出效应的证据。我们还记录了效益显现的条件。补充材料:在线附录见 https://doi.org/10.1287/msom.2022.0519 。
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引用次数: 0
Reliable Frequency Regulation Through Vehicle-to-Grid: Encoding Legislation with Robust Constraints 通过车联网实现可靠的频率调节:用稳健约束编码立法
Pub Date : 2024-02-09 DOI: 10.1287/msom.2022.0154
Dirk Lauinger, François Vuille, Daniel Kuhn
Problem definition: Vehicle-to-grid increases the low utilization rate of privately owned electric vehicles by making their batteries available to electricity grids. We formulate a robust optimization problem that maximizes a vehicle owner’s expected profit from selling primary frequency regulation to the grid and guarantees that market commitments are met at all times for all frequency deviation trajectories in a functional uncertainty set that encodes applicable legislation. Faithfully modeling the energy conversion losses during battery charging and discharging renders this optimization problem nonconvex. Methodology/results: By exploiting a total unimodularity property of the uncertainty set and an exact linear decision rule reformulation, we prove that this nonconvex robust optimization problem with functional uncertainties is equivalent to a tractable linear program. Through extensive numerical experiments using real-world data, we quantify the economic value of vehicle-to-grid and elucidate the financial incentives of vehicle owners, aggregators, equipment manufacturers, and regulators. Managerial implications: We find that the prevailing penalties for nondelivery of promised regulation power are too low to incentivize vehicle owners to honor the delivery guarantees given to grid operators.Funding: This work was supported by the Institut Vedecom.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0154 .
问题定义:通过向电网提供电动汽车电池,"汽车并网 "提高了私人电动汽车的低利用率。我们提出了一个稳健的优化问题,即最大化车主向电网出售一次频率调节的预期利润,并保证在编码了适用法律的功能不确定性集中的所有频率偏差轨迹中,始终满足市场承诺。对电池充放电过程中的能量转换损耗进行忠实建模会使该优化问题变得不凸。方法/结果:通过利用不确定性集的全单调性属性和精确的线性决策规则重述,我们证明了这个具有功能不确定性的非凸稳健优化问题等同于一个可处理的线性程序。通过使用真实世界数据进行广泛的数值实验,我们量化了车辆并网发电的经济价值,并阐明了车主、聚合器、设备制造商和监管机构的经济动机。管理意义:我们发现,目前对未交付承诺调节电量的处罚过低,无法激励车主履行向电网运营商提供的交付保证:本研究得到了 Vedecom 研究所的支持:在线附录见 https://doi.org/10.1287/msom.2022.0154 。
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引用次数: 0
Paid Priority in Service Systems: Theory and Experiments 服务系统中的有偿优先权:理论与实验
Pub Date : 2024-01-19 DOI: 10.1287/msom.2021.0387
Andrew E. Frazelle, Elena Katok
Problem definition: Motivated by the prevalence of paid priority programs in practice, we study a service provider operating a system in which customers have random waiting costs and choose between two queues: regular (no cost) or priority (for a fee). We also consider a mechanism by which the provider redistributes a portion of priority revenue to compensate regular-queue customers for their longer waits. Methodology/results: To determine the waiting-cost-dependent equilibrium priority purchasing strategies, we establish structural results at a sample-path level and prove that they generalize. In models both with and without compensation, the equilibrium exhibits a cost-dependent, increasing-threshold structure. We also prove that compensation entails fewer priority purchases because compensating regular-queue customers makes priority less attractive. We then analyze system-wide performance. Despite the fewer priority purchases, for a fixed (low) priority fee, compensation can actually reduce equilibrium aggregate waiting cost by filtering low-waiting-cost customers out of the priority queue; however, this finding does not hold when comparing at the optimal fees. We then test our models in the laboratory. Key behavioral regularities are that low-cost subjects are overrepresented (underrepresented) in the priority (regular) queue compared with equilibrium, and subjects with low and high waiting costs tend to overbuy priority at high fees. Managerial implications: Our theoretical and behavioral results guide service providers in managing priority service systems. First, we find that compensation does not provide short-term performance benefits. Second, our experiments reveal that suboptimal customer decisions partially prevent efficient reordering of customers by waiting cost, leading to higher aggregate waiting cost than the equilibrium predicts, but still lower than under first-come, first-serve service. Finally, because customers tolerate higher fees than they should, a revenue-maximizing provider can set a higher priority fee and extract more revenue than it could if customers acted rationally.Funding: This work was supported by the Center and Laboratory for Behavioral Operations and Economics at the Naveen Jindal School of Management at The University of Texas at Dallas.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2021.0387 .
问题定义:受付费优先权项目在实践中普遍存在的启发,我们研究了一个服务提供商运营的系统,在这个系统中,客户的等待成本是随机的,他们可以在两个队列中进行选择:普通队列(不收费)或优先队列(收费)。我们还考虑了一种机制,通过这种机制,服务提供商可以重新分配一部分优先权收入,以补偿普通队列客户较长的等待时间。方法/结果:为了确定与等待成本相关的均衡优先购买策略,我们建立了样本路径层面的结构性结果,并证明这些结果具有普遍性。在有补偿和无补偿的模型中,均衡都表现出依赖成本、阈值递增的结构。我们还证明,补偿会减少优先购买,因为补偿普通排队客户会降低优先购买的吸引力。然后,我们分析了整个系统的性能。尽管优先权购买量减少了,但对于固定(低)的优先权费用,补偿实际上可以通过将低等待成本的客户从优先权队列中过滤出来而降低均衡总等待成本;然而,在比较最优费用时,这一结论并不成立。然后,我们在实验室中测试了我们的模型。主要的行为规律是,与均衡时相比,低成本对象在优先(普通)队列中的比例过高(过低),而低等待成本和高等待成本的对象倾向于在高收费时过度购买优先权。管理意义:我们的理论和行为结果为服务提供商管理优先服务系统提供了指导。首先,我们发现补偿并不能带来短期的绩效收益。其次,我们的实验表明,次优客户决策部分地阻止了按等待成本对客户进行有效的重新排序,导致总等待成本高于均衡预测,但仍低于先到先得服务。最后,由于客户容忍的费用比他们应该容忍的要高,收入最大化的提供商可以设定更高的优先级费用,并获得比客户理性行事时更多的收入:本研究得到了德克萨斯大学达拉斯分校纳文-金达尔管理学院行为运营与经济学中心和实验室的支持:在线附录请访问 https://doi.org/10.1287/msom.2021.0387 。
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引用次数: 0
Product Development in Crowdfunding: Theoretical and Empirical Analysis 众筹中的产品开发:理论与实证分析
Pub Date : 2024-01-17 DOI: 10.1287/msom.2022.0344
Sıdıka Tunç Candoğan, Philipp B. Cornelius, Bilal Gokpinar, Ersin Körpeoğlu, Christopher S. Tang
Problem definition: Crowdfunding goes beyond raising funds. Entrepreneurs often use crowdfunding to solicit feedback from customers to improve their products and may therefore prefer to launch their crowdfunding campaigns using basic versions of their products with fewer features. However, customers may not be persuaded by a campaign if the product appears to be underdeveloped. In view of this tradeoff, a key question for entrepreneurs is how much to develop a product before launching a crowdfunding campaign. Methodology/results: Analyzing a game-theoretical model and testing its predictions empirically, we study (1) how the development level of a product at campaign launch, measured by the initial number of product features, influences whether customers will make comments that help entrepreneurs improve the product; (2) whether entrepreneurs continue to improve the product during the campaign; and (3) whether the campaign is successful. We show that, as the number of product features at campaign launch increases, the likelihood that customers will make comments and that the product will be improved during the campaign first increases but then decreases. Furthermore, the likelihood of campaign success first increases but then decreases with the number of product features at campaign launch. Finally, by analyzing the interactions between customer feedback, product improvement, and campaign success, we show that customer feedback motivates entrepreneurs to improve the product during the campaign. Moreover, entrepreneurs should take account of the initial number of features and customer feedback when improving the product, because otherwise product improvements can harm campaign success. Managerial implications: Our study provides practical insights on how entrepreneurs can use crowdfunding to aid product development and improvement. Specifically, entrepreneurs should avoid overdeveloping their products before crowdfunding campaigns because, as well as decreasing the chance of campaign success, this could hinder their ability to save development costs (e.g., market research costs) through involving customers in product development.Supplemental Material: The online appendices are available at https://doi.org/10.1287/msom.2022.0344 .
问题定义:众筹不仅仅是筹集资金。企业家通常利用众筹来征求客户的反馈意见,以改进产品,因此他们可能更愿意使用功能较少的基本版本产品来发起众筹活动。然而,如果产品看起来开发不足,顾客可能不会被活动说服。有鉴于此,创业者面临的一个关键问题是,在发起众筹活动之前,应将产品开发到什么程度。方法/结果:我们分析了一个博弈理论模型,并对其预测进行了实证测试,研究了:(1)以初始产品功能数量衡量的产品在众筹启动时的开发水平如何影响客户是否会提出意见以帮助创业者改进产品;(2)创业者是否会在众筹期间继续改进产品;以及(3)众筹是否成功。我们的研究表明,随着活动启动时产品功能数量的增加,顾客提出意见和产品在活动期间得到改进的可能性先增加后减少。此外,活动成功的可能性会随着活动启动时产品功能数量的增加而先增后减。最后,通过分析客户反馈、产品改进和活动成功之间的相互作用,我们发现客户反馈会激励创业者在活动期间改进产品。此外,创业者在改进产品时应考虑到初始功能数量和客户反馈,否则产品改进会损害活动的成功。管理意义:我们的研究为创业者如何利用众筹帮助产品开发和改进提供了实用的见解。具体而言,创业者应避免在众筹活动前过度开发产品,因为这不仅会降低活动成功的几率,还会阻碍他们通过让客户参与产品开发来节省开发成本(如市场调研成本)的能力:在线附录见 https://doi.org/10.1287/msom.2022.0344 。
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引用次数: 0
What Causes Delays in Admission to Rehabilitation Care? A Structural Estimation Approach 什么原因导致康复护理入院延迟?结构估算法
Pub Date : 2024-01-09 DOI: 10.1287/msom.2022.0377
Jing Dong, Berk Görgülü, Vahid Sarhangian
Problem definition: Delays in admission to rehabilitation care can adversely impact patient outcomes. In addition, delayed patients keep occupying their acute care beds, making them unavailable for incoming patients. Admission delays are mainly caused by a lack of rehabilitation bed capacity and the time required to plan for rehabilitation activities, which we refer to as processing times. Because of non-standard bed allocation decisions and data limitations in practice, quantifying the magnitude of the two sources of delays can be technically challenging yet critical to the design of evidence-based interventions to reduce delays. We propose an empirical approach to understanding the contributions of the two sources of delays when only a single (combined) measure of admission delay is available. Methodology/results: We propose a hidden Markov model (HMM) to estimate the unobserved processing times and the status-quo bed allocation policy. Our estimation results quantify the magnitude of processing times versus capacity-driven delays and provide insights into factors impacting the bed allocation decision. We validate our estimated policy using a queueing model of patient flow and find that ignoring processing times or using simple bed allocation policies can lead to highly inaccurate delay estimates. In contrast, our estimated policy allows for accurate evaluation of different operational interventions. We find that reducing processing times can be highly effective in reducing admission delays and bed-blocking costs. In addition, allowing early transfer—whereby patients can complete some of their processing requirements in the rehabilitation unit—can significantly reduce admission delays, with only a small increase in rehab LOS. Managerial implications: Our study demonstrates the importance of quantifying different sources of delays in the design of effective operational interventions for reducing delays in admission to rehabilitation care. The proposed estimation framework can be applied in other transition-of-care settings with personalized capacity allocation decisions and hidden processing delays.History: This paper was selected for Fast Track in the M&SOM journal from the 2022 MSOM Healthcare SIG Conference.Funding: J. Dong was supported in part by the National Science Foundation [Grant CMMI-1762544]. V. Sarhangian was supported in part by the Natural Sciences and Engineering Research Council of Canada [Grant RGPIN-2018-04518] and the Connaught Fund.Supplemental Material: The e-companion is available at https://doi.org/10.1287/msom.2022.0377 .
问题的定义:延迟康复护理入院会对患者的治疗效果产生不利影响。此外,延迟入院的病人会一直占用急症护理床位,导致无法为新入院的病人提供床位。入院延误的主要原因是康复病床容量不足,以及康复活动计划所需的时间(我们称之为处理时间)。由于床位分配决策的非标准性和实践中数据的局限性,量化这两种延误来源的严重程度在技术上具有挑战性,但对于设计循证干预措施以减少延误至关重要。我们提出了一种实证方法,以了解在只有单一(综合)入院延迟测量指标的情况下,两种延迟来源的贡献。方法/结果:我们提出了一个隐马尔可夫模型(HMM)来估计未观察到的处理时间和现状床位分配政策。我们的估算结果量化了处理时间与容量驱动延迟的大小,并提供了对影响床位分配决策的因素的见解。我们使用病人流排队模型验证了我们的估计政策,发现忽略处理时间或使用简单的床位分配政策会导致非常不准确的延迟估计。相比之下,我们估算的政策可以对不同的运营干预措施进行准确评估。我们发现,缩短处理时间可以非常有效地减少入院延迟和床位阻塞成本。此外,允许提前转院--即患者可以在康复科完成部分处理要求--可以显著减少入院延迟,而康复科的 LOS 只需少量增加。管理意义:我们的研究表明,在设计有效的操作干预措施以减少康复护理入院延误的过程中,量化不同的延误来源非常重要。提出的估算框架可应用于其他具有个性化容量分配决策和隐性处理延迟的护理过渡环境:本文入选 2022 年 MSOM 医疗保健 SIG 会议的 M&SOM 期刊快速通道:J. Dong部分获得了美国国家科学基金会[Grant CMMI-1762544]的资助。V. Sarhangian得到了加拿大自然科学与工程研究委员会[RGPIN-2018-04518号基金]和康诺基金的部分资助:电子版可在 https://doi.org/10.1287/msom.2022.0377 上查阅。
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引用次数: 0
To Earmark or to Nonearmark? The Role of Control, Transparency, and Warm-Glow 指定用途还是不指定用途?控制、透明度和暖光的作用
Pub Date : 2024-01-05 DOI: 10.1287/msom.2022.0096
Özalp Özer, Gloria Urrea, Sebastián Villa
Problem definition: Charities face tension when deciding whether to earmark donations, that is, allow donors to restrict the use of their donations for a specific purpose. Research shows that earmarking decreases operational performance because it limits charities’ flexibility to use donations. However, there is also a common belief that earmarking increases donations. Earmarking is assumed to increase donations through three mechanisms: by (i) giving donors control over their donations, (ii) increasing operational transparency of donations, and (iii) changing donors’ levels of altruism and warm-glow. To resolve this tension, we study how, when, and why earmarking affects donors’ decisions. We consider three important decisions donors make that impact the fundraising outcome: (i) preference between earmarking and nonearmarking, (ii) decision to donate or not (i.e., donor activation), and (iii) the donation amount. Methodology/results: We design three online experiments that allow us to quantify the effect of earmarking on donors’ decisions and to investigate the role of the three aforementioned mechanisms in fundraising. Our results reveal, for example, that earmarking activates more donors but it does not always increase donation amounts. In addition, we determine the conditions under which the three mechanisms affect the outcome of fundraising campaigns. Managerial implications: Our findings provide actionable insights for how charities can design fundraising campaigns more effectively and suggest when to leverage earmarking and the three mechanisms depending on the charities’ fundraising goals.Funding: The authors gratefully acknowledge financial support provided by the Leeds School of Business at the University of Colorado Boulder.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0096 .
问题的定义:慈善机构在决定是否指定捐款用途(即允许捐赠者限制将其捐款用于特定目的)时面临着困难。研究表明,指定用途会降低运营绩效,因为它限制了慈善机构使用捐款的灵活性。然而,人们也普遍认为指定用途会增加捐款。指定用途被认为可以通过三种机制增加捐赠:(i) 让捐赠者控制自己的捐赠;(ii) 增加捐赠运作的透明度;(iii) 改变捐赠者的利他主义和热忱水平。为了解决这一矛盾,我们研究了指定用途如何、何时以及为何会影响捐赠者的决策。我们考虑了捐赠者做出的影响筹款结果的三个重要决定:(i) 对指定用途和不指定用途的偏好,(ii) 是否捐赠的决定(即捐赠者激活),以及 (iii) 捐赠金额。方法/结果:我们设计了三个在线实验,以量化指定用途对捐赠者决定的影响,并研究上述三种机制在筹款中的作用。例如,我们的结果表明,指定用途能激活更多的捐赠者,但并不总是能增加捐赠金额。此外,我们还确定了三种机制影响筹款活动结果的条件。管理意义:我们的研究结果为慈善机构如何更有效地设计筹款活动提供了可操作的见解,并建议根据慈善机构的筹款目标何时利用指定用途和三种机制:作者衷心感谢科罗拉多大学博尔德分校利兹商学院提供的资金支持:在线附录见 https://doi.org/10.1287/msom.2022.0096 。
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引用次数: 0
Decarbonizing OCP OCP 的去碳化
Pub Date : 2023-12-28 DOI: 10.1287/msom.2022.0467
Dimitris Bertsimas, Ryan Cory-Wright, Vassilis Digalakis
Problem definition: We present our collaboration with the OCP Group, one of the world’s largest producers of phosphate and phosphate-based products, in support of a green initiative designed to reduce OCP’s carbon emissions significantly. We study the problem of decarbonizing OCP’s electricity supply by installing a mixture of solar panels and batteries to minimize its time-discounted investment cost, plus the cost of satisfying its remaining demand via the Moroccan national grid. OCP is currently designing its renewable investment strategy, using insights gleaned from our optimization model, and has pledged to invest 130 billion Moroccan dirham (MAD) (approximately 13 billion U.S. dollars (USD)) in a green initiative by 2027, a subset of which involves decarbonization. Methodology/results: We immunize our model against deviations between forecast and realized solar generation output via a combination of robust and distributionally robust optimization. To account for variability in daily solar generation, we propose a data-driven robust optimization approach that prevents excessive conservatism by averaging across uncertainty sets. To protect against variability in seasonal weather patterns induced by climate change, we invoke distributionally robust optimization techniques. Under a 10 billion MAD (approximately 1 billion USD) investment by OCP, the proposed methodology reduces the carbon emissions that arise from OCP’s energy needs by more than 70%, while generating a net present value (NPV) of 5 billion MAD over a 20-year planning horizon. Moreover, a 20 billion MAD investment induces a 95% reduction in carbon emissions and generates an NPV of around 2 billion MAD. Managerial implications: To fulfill the Paris climate agreement, rapidly decarbonizing the global economy in a financially sustainable fashion is imperative. Accordingly, this work develops a robust optimization methodology that enables OCP to decarbonize at a profit by purchasing solar panels and batteries. Moreover, the methodology could be applied to decarbonize other industrial consumers. Indeed, our approach suggests that decarbonization’s profitability depends on solar capacity factors, energy prices, and borrowing costs.History: This paper has been accepted as part of the 2023 Manufacturing & Service Operations Management Practice-Based Research Competition.Supplemental Material: The e-companion is available at https://doi.org/10.1287/msom.2022.0467 .
问题定义:我们介绍了与世界上最大的磷酸盐和磷酸盐基产品生产商之一 OCP 集团的合作,以支持一项旨在大幅减少 OCP 碳排放的绿色倡议。我们研究的问题是,通过安装太阳能电池板和电池的混合物,使 OCP 的电力供应去碳化,从而最大限度地降低其时间贴现投资成本,以及通过摩洛哥国家电网满足其剩余需求的成本。OCP 目前正在利用我们从优化模型中获得的见解设计其可再生能源投资战略,并承诺在 2027 年前投资 1300 亿摩洛哥迪拉姆(约合 130 亿美元)用于绿色计划,其中一部分涉及去碳化。方法/结果:我们通过稳健优化和分布稳健优化相结合的方法,使模型免受预测与实际太阳能发电量之间偏差的影响。为了考虑每日太阳能发电量的变化,我们提出了一种数据驱动的稳健优化方法,通过对不确定性集进行平均,防止过度保守。为了防止气候变化引起的季节性天气模式的变化,我们采用了分布稳健优化技术。在 OCP 投资 100 亿马其顿第纳尔(约 10 亿美元)的情况下,所建议的方法可将 OCP 能源需求产生的碳排放量减少 70% 以上,同时在 20 年规划期内产生 50 亿马其顿第纳尔的净现值 (NPV)。此外,200 亿马币的投资可减少 95% 的碳排放量,并产生约 20 亿马币的净现值。管理意义:为了履行巴黎气候协议,以财政可持续的方式快速实现全球经济的去碳化势在必行。因此,本研究开发了一种稳健的优化方法,使 OCP 能够通过购买太阳能电池板和电池来实现去碳化,并从中获利。此外,该方法还可应用于其他工业消费者的去碳化。事实上,我们的方法表明,去碳化的盈利能力取决于太阳能容量系数、能源价格和借贷成本:本论文已作为 2023 年制造业& 服务业运营管理实践研究竞赛的一部分被接受:电子附录可在 https://doi.org/10.1287/msom.2022.0467 上获取。
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引用次数: 0
Inventory Productivity and Stock Returns in Manufacturing Networks 制造网络中的库存生产力和库存回报
Pub Date : 2023-12-22 DOI: 10.1287/msom.2022.0229
Deepak Agrawal, Nikolay Osadchiy
Problem definition: We provide a novel, supply network-based perspective on inventory productivity and incentives for its improvement. Methodology/results: Using data from 2003 to 2019, we find that inventory productivity is lower materially and statistically for firms located upstream in the supply network, and higher for high degree and more central firms. Firms with high inventory productivity show high equity valuations and abnormal returns, with both valuations and abnormal returns amplified for upstream, low degree, and peripheral firms. Moreover, the difference in valuations and abnormal returns between best and worst performing firms is greater upstream, suggesting that financial markets offer outsized rewards for improving inventory productivity to upstream firms. Managerial implications: We show that the information about firm’s upstreamness and centrality in the supply network is a valuable predictor of its inventory productivity and financial performance. Our methods for evaluating upstreamness are useful for that purpose. For operations managers and firm executives, our results highlight strong incentives for inventory productivity improvement upstream in the supply network. For investors, we show that supply network position data can sharpen inventory-based arbitrage opportunities.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0229 .
问题定义:我们提供了一种基于供应网络的库存生产率新视角,以及提高库存生产率的激励措施。方法/结果:利用 2003 年至 2019 年的数据,我们发现位于供应网络上游的企业的库存生产率在实质上和统计上都较低,而程度高、更集中的企业的库存生产率较高。库存生产率高的企业显示出高股票估值和异常回报,上游、低程度和边缘企业的估值和异常回报都会放大。此外,表现最好和最差的公司之间的估值和异常收益差异在上游更大,这表明金融市场为上游公司提高存货生产率提供了超额回报。管理意义:我们的研究表明,企业在供应网络中的上游地位和中心地位是预测其库存生产率和财务业绩的重要指标。我们评估上游性的方法在这方面非常有用。对于运营经理和公司高管来说,我们的研究结果凸显了在供应网络上游提高库存生产率的强烈动机。对于投资者来说,我们的结果表明,供应网络中的仓位数据可以增加基于库存的套利机会:在线附录见 https://doi.org/10.1287/msom.2022.0229 。
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引用次数: 0
Waste Not Want Not? The Environmental Implications of Quick Response and Upcycling 不要浪费?快速反应和升级再造对环境的影响
Pub Date : 2023-12-21 DOI: 10.1287/msom.2022.0040
Xiaoyang Long, Luyi Gui
Problem definition: Overproduction is often cited as the fashion industry’s biggest environmental issue, as textile production is notoriously resource intensive and pollutive, and much of the textile produced may end up as “deadstock” fabric or finished goods that do not sell. In this paper, we study two major approaches to address this issue: quick response, whereby finished goods inventory is replenished on demand, and upcycling, whereby deadstock fabric is reused to make new clothes. Proponents of these strategies typically focus on their positive environmental impact in downstream supply chain stages (e.g., finished goods production and waste disposal). Less is known, however, about their impact on upstream activities such as raw material acquisition, which we investigate in this work. Methodology/results: We analyze the effect of quick response and upcycling options on firms’ fabric acquisition and production decisions, as well as firms’ incentives to adopt these strategies. We then assess these strategies’ environmental impact in a life cycle framework. Our results show that quick response—when implemented in isolation—reduces deadstock of finished goods, but could increase the amount of fabric acquired. This not only results in more total deadstock (in both finished goods and fabric form), but also aggravates the environmental burden associated with fabric production in the upstream of the fashion supply chain, and could lead to a worse overall environmental impact for the industry. Upcycling together with quick response could alleviate total deadstock generation, but further increases the firm’s demand for fabric. We analyze the effectiveness of two types of policies—subsidizing quick response/upcycling and banning deadstock destruction—in reducing deadstock and curbing firms’ need for fabric. Managerial implications: Our work highlights a tradeoff between downstream deadstock reduction and upstream fabric acquisition, and suggests that regional policies that aim to reduce local deadstock could often have adverse global impacts.Supplemental Material: The online appendices are available at https://doi.org/10.1287/msom.2022.0040 .
问题定义:过度生产经常被认为是时尚产业最大的环境问题,因为纺织品生产是众所周知的资源密集型和污染型产业,而且生产的大部分纺织品最终可能成为 "库存 "面料或滞销成品。在本文中,我们研究了解决这一问题的两种主要方法:快速反应法,即根据需求补充成品库存;升级再造法,即重新利用库存织物制作新衣服。这些策略的支持者通常关注其对下游供应链阶段(如成品生产和废物处理)的积极环境影响。然而,我们对这些策略对上游活动(如原材料采购)的影响知之甚少。方法/结果:我们分析了快速反应和升级再造方案对企业面料采购和生产决策的影响,以及企业采取这些策略的动机。然后,我们在生命周期框架内评估了这些策略对环境的影响。我们的结果表明,单独实施快速反应可减少成品库存,但会增加面料采购量。这不仅会导致更多的库存总量(包括成品和面料),还会加重时装供应链上游面料生产对环境造成的负担,并可能导致整个行业对环境产生更严重的影响。升级再造和快速反应可减轻库存总量,但会进一步增加企业对面料的需求。我们分析了两种政策--补贴快速反应/升级再造和禁止销毁库存--在减少库存和抑制企业对面料需求方面的有效性。对管理的影响:我们的研究强调了减少下游库存和获取上游面料之间的权衡,并表明旨在减少本地库存的地区政策往往会对全球产生不利影响:在线附录见 https://doi.org/10.1287/msom.2022.0040 。
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引用次数: 0
Online Learning for Dual-Index Policies in Dual-Sourcing Systems 双源系统中双指数政策的在线学习
Pub Date : 2023-12-12 DOI: 10.1287/msom.2022.0323
Jingwen Tang, Boxiao Chen, Cong Shi
Problem definition: We consider a periodic-review dual-sourcing inventory system with a regular source (lower unit cost but longer lead time) and an expedited source (shorter lead time but higher unit cost) under carried-over supply and backlogged demand. Unlike existing literature, we assume that the firm does not have access to the demand distribution a priori and relies solely on past demand realizations. Even with complete information on the demand distribution, it is well known in the literature that the optimal inventory replenishment policy is complex and state dependent. Therefore, we focus our attention on a class of popular, easy-to-implement, and near-optimal heuristic policies called the dual-index policy. Methodology/results: The performance measure is the regret, defined as the cost difference of any feasible learning algorithm against the full-information optimal dual-index policy. We develop a nonparametric online learning algorithm that admits a regret upper bound of [Formula: see text], which matches the regret lower bound for any feasible learning algorithms up to a logarithmic factor. Our algorithm integrates stochastic bandits and sample average approximation techniques in an innovative way. As part of our regret analysis, we explicitly prove that the underlying Markov chain is ergodic and converges to its steady state exponentially fast via coupling arguments, which could be of independent interest. Managerial implications: Our work provides practitioners with an easy-to-implement, robust, and provably good online decision support system for managing a dual-sourcing inventory system.Funding: This work was supported by the Amazon Research Award.Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0323 .
问题定义:我们考虑的是在结转供应和需求积压的情况下,一个周期性回顾的双源库存系统,其中有一个常规源(单位成本较低,但交货期较长)和一个加速源(交货期较短,但单位成本较高)。与现有文献不同的是,我们假定企业无法事先获得需求分布,只能依赖过去的需求实现情况。众所周知,即使拥有关于需求分布的完整信息,最优库存补充政策也是复杂的,而且与状态有关。因此,我们将注意力集中在一类流行、易于实施且接近最优的启发式政策上,即双指数政策。方法/结果:性能的衡量标准是 "遗憾",它被定义为任何可行的学习算法与全信息最优双指数策略的成本差异。我们开发了一种非参数在线学习算法,该算法的遗憾值上限为[公式:见正文],与任何可行学习算法的遗憾值下限相差一个对数因子。我们的算法以创新的方式整合了随机匪帮和样本平均逼近技术。作为遗憾分析的一部分,我们明确证明了底层马尔科夫链是遍历的,并通过耦合论证以指数级速度收敛到其稳态,这可能会引起独立的兴趣。管理意义:我们的工作为从业人员提供了一个易于实施、稳健且可证明良好的在线决策支持系统,用于管理双源库存系统:这项工作得到了亚马逊研究奖的支持:在线附录见 https://doi.org/10.1287/msom.2022.0323 。
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引用次数: 0
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Manufacturing & Service Operations Management
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