Modeling Reputation as a Time‐Series: Evaluating the Risk of Purchase Decisions on eBay*

Reputation systems based on buyer feedback play an important role in today's online markets. In this article, we provide a rigorous methodology to establish a relationship between a seller's feedback history and risk of default. We validate this method against eBay's reputation system, using a dataset of terminated users (Not‐A‐Registered‐User or NARU) and the feedback left for them by buyers. By treating feedback rating data as a function of time, we characterize the tendency of change in seller feedback ratings in order to predict the behavior of a seller. We find that NARU sellers have significantly more negative feedback in their final weeks. Applying functional principal component analysis and classification tree methods, we find that when projecting the feedback data to an appropriate space, NARU and non‐NARU sellers can be distinguished at better than 92% accuracy. We use this to provide a quantitative mechanism for evaluating the risk of trading with a seller who has less than perfect feedback, and offer advice on how much a buyer should offer to pay, given an asking price on a commodity item and a seller's feedback history.     

基于收益共享契约的网络零售联合促销策略研究

网络零售业造节促销已成常态,优化网络零售平台(简称平台商)和销售商联合促销策略是一项值得深入研究的课题。本文基于收益共享契约,利用不同的博弈模型刻画入驻销售商和平台商之间三种不同的促销模式,包括由其中一方率先发起促销的模式和二者同时发起促销的模式,研究不同模式下销售商和平台商的最优促销策略。研究结论表明,在三种促销模式下,二者的最优促销策略均随着商品佣金费率的增长依次呈现三种不同的形式:从仅由销售商提供促销到联合促销再到仅由平台商提供促销。当且仅当佣金费率和商品的日常售价高于一定阈值时,销售商和平台商才会有动机开展联合促销。研究还发现,销售商和平台商在各自率先发起的联合促销模式下具备先动优势。销售商(平台商)率先发起的联合促销将更有利于对佣金费率较低(高)的商品实施。当销售商和平台商同时独立发起促销时,供应链整体促销力度最大,供应链的整体利润也最高。     

双边市场中平台企业搭售行为分析

搭售是现实中双边平台企业常用的促销策略之一。通过构建一个两阶段完全信息动态博弈模型,将买方分为搭售喜好型和搭售无差异型,从垄断和竞争两种情形研究了双边平台企业采取搭售策略时,具有不同搭售偏好的买方对最优均衡解的影响以及相应的社会福利变化。研究发现:不论是垄断情形还是竞争情形,搭售对买卖双方均衡进入价格的影响都不确定,而搭售产品的定价则按照传统单边市场的定价方式制定;垄断情形下,搭售能增加买方数量、卖方数量及双边平台企业的利润,而竞争情形下,搭售产品成本较小的双边平台企业将获得较大买方数量、卖方数量及利润。在两种情形下的买方总效用、卖方总效用以及社会总福利均随搭售喜好型买方数量的增加而增加。     

Nonexclusive Competition in the Market for Lemons

A seller can trade an endowment of a perfectly divisible good, the quality of which she privately knows. Buyers compete by offering menus of nonexclusive contracts, so that the seller can privately trade with several buyers. In this setting, we show that an equilibrium exists under mild conditions and that aggregate equilibrium allocations are generically unique. Although the good for sale is divisible, in equilibrium the seller ends up trading her whole endowment or not trading at all. Trades take place at a price equal to the expected quality of the good, conditional on the seller being ready to trade at that price. Our model thus provides a novel strategic foundation for Akerlof's (1970) results. It also contrasts with competitive screening models in which contracts are assumed to be exclusive, as in Rothschild and Stiglitz (1976). Latent contracts that are issued but not traded in equilibrium play an important role in our analysis.     

考虑社交关系的网购拼单研究

本文提供理论模型对比分析拼单模式和统一价格模式(正常模式)给商家带来的影响，为商家实施精准营销提供参考。对此，首先考虑消费者的社交关系并以此将消费者进行细分，随后分析社交关系的成本系数(社交成本)和潜在市场需求对价格和收益的影响。结果指出，在一定条件下，拼单模式可以为商家带来了更大的收益，但是拼单模式只是正常模式的一种补充，并且随着两类消费者的社交成本差额逐渐变小或偏好拼单的消费者的潜在市场需求不断增加，拼单模式的优势逐渐减弱。因此，建议电商平台与微信等社交平台合作，降低消费者的社交成本，以吸引消费者通过拼单模式购买商品，从而实现“商家、平台和消费者” 多方共赢。最后建议，平台对消费者进行二次或三次细分，开发新的细分市场。     

双寡头电商平台的收费制度选择博弈

在竞争环境下,考虑两个开放型电商平台寡头主导的电商服务链,两平台对网商的收费制度为注册收费制、交易收费制、两部收费制等三种收费制度构成的策略集,本文构建了两平台的六种收费制度组合模型。通过博弈论逆序求解法和划线法分析发现:当平台的注册服务成本不低于交易服务成本时,两平台对网商的收费制度选择博弈不一定存在均衡,存在则必为其中一方采取交易收费制而另一方采取两部收费制这种分离均衡;反之,两平台对网商的收费制度选择博弈必定存在均衡,且为双方均选择注册收费制这种混同均衡。     

The seller's perspective on acquisition success: Empirical evidence from the communications equipment industry

This paper considers acquisition success from the seller's perspective and uses the seller's acquisition success criteria as an indication of their interpretation of the acquisition event. The argument is that sellers who use strategic and social criteria to appraise acquisition success interpret acquisitions as partnerships, while sellers who use financial criteria to appraise success interpret acquisitions as sales. Based on interview and survey data on the seller's perspective on acquisition success for 33 acquisitions in the communications equipment industry, we find that sellers use strategic and social criteria to appraise acquisition success and conclude that sellers interpret acquisitions as partnerships.     

不同市场能力下的“电商—平台—物流”在线销售系统的决策研究

近年来,随着互联网的快速发展,市场上衍生出了一些在线销售网站。考虑了一个包含电商卖家、电商平台和物流公司的在线销售系统模型,其中需求依赖于产品价格、平台和物流服务水平。研究了当物流、平台同时决策时,在线销售系统中电商卖家和平台、物流之间的不同市场能力结构问题。考虑了3种不同市场能力的分散决策模型:(1)物流-平台Stackelberg模型;(2)电商Stackelberg模型;(3)Nash模型。相关的均衡解和最优利润被得到。研究结果表明,在不同的市场能力结构下,当物流公司和平台同时决策时,即使他们的服务投入不相同,但最优收费相同。市场能力结构对在线销售成员和消费者有重要的影响。对电商而言,当市场能力较高时,会制定较低的零售价格,并获得最多的利润,同时能够提升消费者购买的积极性;当市场能力较低时,电商会制定较高的零售价格,并获得最少的利润。对平台和物流公司而言,当市场能力较高时,会制定比较高的收费,同时付出较少的努力,但并不能获得最高利润,同时会打击消费者的积极性;但是,当市场能力较低时,他们一定获得最少的利润。在Nash模型中,平台和物流公司会付出最大的努力,同时获得最大的利润,而整个在线销售系统的总利润也是最多。在物流-平台Stackelberg模型中,平台和物流公司付出的努力最少,而整个在线销售系统的总利润也最少。     

考虑鉴真服务和消费者偏好的混合E-供应链决策研究

鉴真服务平台通过提供鉴真服务,为线上商品的出售提供了质量保障,切实提高了消费满意度,降低了线上产品退货率。对此,本文构建了由鉴真服务E-供应链和传统E-供应链组成的混合E-供应链系统;运用Stackelberg博弈,求解集中式和分散式决策下的最优定价策略及利润;分析鉴真努力程度对各模型运作的影响,并对不同模型的最优决策进行比较;最后通过数值分析,对模型结论进行验证。研究表明：1)无论是集中式决策还是分散式决策,两个渠道的产品销售价格均随鉴真努力程度的增大而增加,而混合E-供应链总利润随鉴真努力程度的增大先减小后增大;2)分散式决策模式中,鉴真渠道的产品销售价格在销售商主导模型下更高,而销售商总利润和鉴真平台利润在鉴真平台主导模型下更高,且鉴真平台所获取的佣金及鉴真平台的利润均随鉴真努力程度的增大而增加,销售商总利润随鉴真努力程度的增加先减小后增大;3)集中式决策模式中混合E-供应链的总利润最高,且此时主要利润为销售商所得。本文的研究进一步丰富和发展了混合E-供应链决策理论,而且为鉴真服务平台和线上销售商的经营决策提供参考。     

基于好评返现和差评偏好的体验型产品两阶段定价决策研究

假定产品存在发布试销期与正式销售期,在销售商不采取好评返现与采取好评返现两种情形下分别建立考虑消费者差评偏好的两阶段定价决策模型,用KT方法得到相应的最优决策和利润,给出了销售商实施好评返现的条件。基于导函数分析方法与数值仿真技术,分析了好评返现与差评偏好对产品定价、销售商利润和消费者效用的影响,证实了好评返现下消费者重视差评信息的合理性,并针对消费者、平台和销售商提出了对策。研究表明:只有产品质量中等的销售商才会采取好评返现策略,其利润随产品质量的提升而先递增后递减;好评返现提高了销售商第二阶段的市场份额和售价,导致消费者效用损失;消费者越重视差评信息,实施好评返现的高(低)质量产品销售商越多(少),且销售商利润将下降;好评返现扭曲了评价信息的真实性,降低了消费者对在线评价系统的信任度。     

Ranked Items Auctions and Online Advertisement

We study auctions for a set of commonly‐ranked items where each buyer has unit demand. This setting has promising applications in areas such as keyword auctions in the search engine advertising industry, the sale of quality‐ranked raw materials, etc. An auction mechanism suitable for this setting is the simultaneous pooled auction (SPA), where each bidder simultaneously submits a single bid and is allocated an object based on the rank of his bid among all the bids. We study how to improve the seller's expected revenue by enforcing a reserve price in an SPA. We find that the use of an appropriate reserve price may significantly increase the seller's revenue, especially when the number of items for sale is relatively large compared to the number of participating bidders. One inherent problem in the SPA is that some bidders may incur ex post losses; that is, they pay more than what they value the received objects. We propose a tailored VCG mechanism that generates the same expected revenue as the SPA does, while bidders do not incur any ex post loss. We also discuss the potential applications of this research to keyword auctions.     

Optimal Fee Structures of Crowdsourcing Platforms

Crowdsourcing platforms specialize in hosting open contests and usually charge a percentage of the prizes as service fees. While prior research has studied the design of contests and the behavior of contestants, the strategy of a crowdsourcing platform has remained largely unexplored. We develop a game‐theoretic model of crowdsourcing services and find the optimal fee structure of a platform. We prove for the case of a single contest that the service fees should be an increasing concave function of task prizes and show that this also holds true for the case of multiple contests. We further find that for a platform with many users and tasks, there is an optimal ratio of the number of contestants and contests. Our research is one of the first to focus on the strategies of crowdsourcing platforms and our results have interesting managerial implications. We show that the linear fee schedule widely used in practice is not optimal and that a platform is better off lowering the fee rate for contests with high prizes. It is also in the best interests of a platform to develop both sides of the crowdsourcing market proportionally and keep the ratio of contestants and contests at the optimal level.      

MARKET POWER AND INFORMATION REVELATION IN DYNAMIC TRADING

We study a strategic model of dynamic trading where agents are asymmetrically informed over common value sources of uncertainty. There is a continuum of buyers and a finite number n of sellers. All buyers are uninformed, while at least one seller is privately informed about the true state of the world. When n = 1, full information revelation never occurs in equilibrium and the only information transmission happens in the first period. With n > 1 the outcome depends both on the structure of the sellers' information and, even more importantly, on the intensity of competition allowed by the existing trading rules. When there is intense competition (absence of clienteles), information is fully and immediately revealed to the buyers in every equilibrium for n large enough, regardless of the number of informed sellers. On the other hand, for trading arrangements characterized by less intense forms of competition (presence of clienteles), for any n we always have equilibria where information is never fully revealed. Moreover, in that case, when only one seller is informed, for many parameter configurations there are no equilibria with full information revelation, even for large n. (JEL: C72, C78, D82, D83)     

Group Buying,Buyer Heterogeneity,and Sellers' Bargaining Power*

Group buying enables collective bargaining opportunity that individual buyers lack to negotiate prices with sellers. This potential negotiation capability has two opposing effects. On the one hand, the prospect of the group being able to negotiate price with its rival forces each seller to lower its price offer, as too high a price will induce the group to give its rival an opportunity to undercut its price via negotiation, likely taking away all the buyers. On the other hand, the potential negotiation opportunity may also discourage sellers from competing aggressively in their price offers, as the benefit of charging a low price could be offset by competitors in negotiation, thus yielding overall higher prices for the buyers. In this study, we find that compared to individual purchase, buyers benefit from collective bargaining opportunity by group buying only if sellers’ bargaining power relative to the buyer group is low and/or buyers’ preferences toward the sellers are sufficiently differentiated. Given buyers’ strategic choice of group purchase, sellers may be worse off with a further increase in bargaining power, and so may social welfare.     

在线拍卖中的“托”出价研究

本文分析了独立的私人估价环境下最优保留价格与竞买人数之间的关系,纠正了最优保留价格与竞买人数无关的传统观点.在此基础上,讨论了卖者可能递交"托"出价的条件以及拍卖中只剩下一个竞买人时卖者的最优"托"出价.     

网络销售中退货担保与定价决策

本文采用退货担保期权综合完全退货策略与部分退货策略的优点,构建了网络销售中基于期权的退货与定价模型,以商品的价格、退货策略和退货担保期权价格为决策变量,讨论了存在退货期权和不存在退货期权两种情况下,最优决策存在的条件,求解出销售商最优价格、退货策略和退货担保期权价格,分析了各个市场参数变化对最优值的影响,通过对担保退货期权与退货策略同时存在和购买期权才能退货二种策略的比较,发现供应商最优策略是前者。算例验证了以上结论,做了敏感性分析,总结了相关管理启示与未来研究方向。所得结论对网络销售商开展网上销售有重要参考价值。     

Dynamic Matching,Two‐Sided Incomplete Information,and Participation Costs: Existence and Convergence to Perfect Competition

Consider a decentralized, dynamic market with an infinite horizon and participation costs in which both buyers and sellers have private information concerning their values for the indivisible traded good. Time is discrete, each period has length δ, and, each unit of time, continuums of new buyers and sellers consider entry. Traders whose expected utility is negative choose not to enter. Within a period each buyer is matched anonymously with a seller and each seller is matched with zero, one, or more buyers. Every seller runs a first price auction with a reservation price and, if trade occurs, both the seller and the winning buyer exit the market with their realized utility. Traders who fail to trade continue in the market to be rematched. We characterize the steady‐state equilibria that are perfect Bayesian. We show that, as δ converges to zero, equilibrium prices at which trades occur converge to the Walrasian price and the realized allocations converge to the competitive allocation. We also show the existence of equilibria for δ sufficiently small, provided the discount rate is small relative to the participation costs.     

电商平台扣点率影响下的双渠道供应链协调定价研究

电商平台通常对入驻企业征收技术服务费、推广费用和促销活动费用等,这部分费用占销售额的比例即电商平台扣点率成为影响入驻企业定价的重要因素。有鉴于此,本文研究了电商平台扣点率影响下的双渠道供应链协调定价问题。首先构建了追求供应链整体利润最大化的集中式定价模型,得出最优线上、线下渠道销售价格,分析了扣点率影响下的价格、销量与利润变化,逐步确定了扣点率的决策范围。然后以分散式决策下企业最优利润为基准设计基于Shapley值的协调定价方案以确定最优线下渠道批发价格,给出了协调后的最优定价,最后使用Mathematica 11软件进行了数值分析与仿真。这一研究对解释电商平台扣点率影响下的双渠道供应链协调定价机制与相关指标的变化,实现企业和电商平台的良性互动具有重要意义。     

不同线上销售模式的产品定价策略研究

现售和预售是线上销售的主要模式。考虑不同模式下消费者对产品估值的差异,分析现售、预售和混合销售（同时开展现售和预售）三种模式下消费者购买决策过程,构建Stackelberg博弈和Nash均衡模型,得到三种模式的产品均衡定价及需求,并探讨开展不同销售模式对应的消费者估值差异阈值以及不同主导结构对供应链企业绩效的影响。结果表明：任意主导结构下,销售模式只会影响现售产品价格,对预售产品定价没有影响;任意销售模式下,制造商主导结构的产品定价和批发价更高,但产品销售量较低;消费者延迟收货敏感度增强使预售模式的供应链成员企业的利润降低,但混合销售模式可以有效防止由此引起的损失,且制造商主导可以同时实现供应链成员企业的利益最大化。     

The strategic analysis of logistics service sharing in an e-commerce platform

In e-commerce, the success of hybrid online platforms is well documented where the platform not only works as a retailer but also offers online marketplace services to sellers. Logistics service is one of the most expensive operations for e-commerce and plays a critical role in promoting online purchases. In most cases, the platform builds a self-supporting logistics service system to deliver its own products, and the seller outsources the logistics service to third-party logistics service providers (TPLPs). Recently, the e-commerce market has emerged with a new trend of business-to-business logistics service sharing—the platform shares its logistics service system with the seller. In this paper, we first analyze the strategic and economic impacts of logistics service sharing. Our analysis shows that whereas logistics service sharing will lead to a lose-win situation for the platform and the seller when the TPLP's logistics service level and the market potential are low, it will lead to a win-lose situation when the TPLP's logistics service level or the market potential is very high. Furthermore, a win-win situation can be achieved when the TPLP's logistics service level and the market potential are in the middle regions. Then, we examine the equilibrium mode by considering the strategic interactions between the platform and the seller. We find that when the TPLP's logistics service level and the market potential are relatively low, the equilibrium mode is No-Service-Sharing. As the TPLP's logistics service level, the market potential, or both increase, the equilibrium mode will evolve from No-Service-Sharing to Service-Sharing.