cores of inventory centralization games abstract consider a set of n stores with single item and single period demands assume an option of centralized ordering and inventory with holding and penalty costs only in this case a cooperative inventory centralization game defines allocations of the cost we examine the conditions under which such an inventory centralization game has a nonempty core we prove the existence of nonempty core for demands with symmetric distributions and the existence of nonempty core for joint multivariate normal demand distribution we establish the equivalency of four different nonempty core conditions for the newsboy problem and demonstrate their efficacy for discrete independent and identically distributed iid demands journal of economic literature classification numbers c44 c62 c71

collaborative replenishment in the presence of intermediaries in complex supply chains downstream buyers would often replenish individually from intermediaries instead of directly dealing with original manufacturers although collaborative replenishment from intermediaries might generate benefits significant cost reductions could be achieved when direct replenishments from manufacturers are considered this paper constructs a general model to study collaborative replenishment in multi product chains with alternative sources of supply i e manufacturers and intermediaries a collaborative organization determines the optimal choices of replenishment sources on behalf of its members to minimize collective costs we introduce a class of cooperative games associated with these situations and give sufficient conditions for their concavity we investigate the choice of allocation rule and its effect on supply chain efficiency when buyers strategically participate in the collaborative organization we prove that the shapley value coordinates the supply chain i e it makes complete participation the best strategy for buyers even under asymmetric information this setting is compared with an alternative structure where buyers can only collaborate in source specific replenishment organizations that purchase all requested products either from intermediaries or manufacturers although there are always participation strategies that result in minimum collective cost it is impossible to find allocation rules for source specific replenishment organizations that always motivate the buyers to choose such strategies

behavioral causes of the bullwhip effect and the observed value of inventory information the tendency of orders to increase in variability as one moves up a supply chain is commonly known as the bullwhip effect we study this phenomenon from a behavioral perspective in the context of a simple serial supply chain subject to information lags and stochastic demand we conduct two experiments on two different sets of participants in the first we find the bullwhip effect still exists when normal operational causes e g batching price fluctuations demand estimation etc are removed the persistence of the bullwhip effect is explained to some extent by evidence that decision makers consistently underweight the supply line when making order decisions in the second experiment we find that the bullwhip and the underlying tendency of underweighting remains when information on inventory levels is shared however we observe that inventory information helps somewhat to alleviate the bullwhip effect by helping upstream chain members better anticipate and prepare for fluctuations in inventory needs downstream these experimental results support the theoretically suggested notion that upstream chain members stand to gain the most from information sharing initiatives

the newsvendor game has a nonempty core we settle an open conjecture regarding the newsvendor game we prove that its core is always non empty for all possible joint distributions of the random demands we give sufficient conditions under which the core is a singleton or it contains non negative elements

the implications of competition among jurisdictions does tiebout need politics the paper investigates whether compensation among local jurisdiction is by itself sufficient to ensure efficient provision of local public goods jurisdictions have fixed boundaries and each has an entrenched government with the power to tax and supply the public good residents can move costlessly among jurisdictions it is shown that competition among numerous jurisdictions is not sificient to guarantee public sector efficiency though residents can vote with their feet land is immobile hence governments can unsurp some land rents for their own ends increasing the number of jurisdictions limits but cannot completely eliminate the ability to exercise discretionary governmental power

heterogeneity within communities a stochastic model with tenure choice standard explanations for the income heterogeneity within neighborhoods rely on differences of preferences across households and heterogeneity of the housing stock we propose an alternative and complementary explanation we construct a stochastic equilibrium sorting model where 1 income is the sole dimension of household heterogeneity 2 households form state contingent housing location plans that may involve moves over their lifetimes 3 households choose whether to own or rent depending on the housing expenditure risk associated with each tenure mode and 4 there is a probability that newcomer households move in and compete for homes with native households income mixing within neighborhood arises for two reasons first allowing natives to form state contingent housing location plans breaks the indivisibility of housing consumption implicit in the literature where households choose their location once and for all second natives can insure themselves against rent fluctuations by buying their home prior to the realization of the population shock newcomers cannot as a result poorer natives stay in the more desirable communities and only richer newcomers move in these communities evidence from u s metropolitan areas supports the effects predicted by the model

second best taxation as a game second best theory usually lies in the realm of normative analysis it focuses attention on the best solutions which still can be obtained in problems where constraints of various natures forbid the attainment of first best pareto optimal situations its central concern is the characterization of such second best solutions and a large part of the literature concentrates on the optimal design of taxes or of policies of public firms taking a second best problem we try in this paper to shift the emphasis from normative to positive considerations the solution we are interested in is not optimal with respect to some a priori given social welfare function embodying justice objectives but it is supposed to reflect the power of the different agents in a negotiation process clearly the conceptual tools required for such an analysis are to be found in game theory and it is actually a game theoretical approach that we follow here the model we are looking at is presented in section ii it formalizes one of the simplest second best problems that can be imagined we have a twogood economy with one private good and one public good agents have different wealth in private good and the public good is financed through a wealth tax this latter fiscal system is clearly not flexible enough to adjust contributions with marginal willingnesses to pay so that we actually face a second best situation there is one decision variable in the society the tax rate which determines the public good production about which the agents have conflicting desires to this problem we associate a game which provides a precise framework for the analysis of the power of the agents the positive outcomes of the negotiation process are supposed to belong to the core of this game sections iii and iv concentrate on the analysis of the core the results strongly contrast with those obtained in the classical studies of the core of 67 0022 053 l 81 040067 25 02 00 o

the competitive newsboy we consider a competitive version of the classical newsboy problem in which a firm must choose an inventory or production level for a perishable good with random demand and the optimal solution is a fractile of the demand distribution and investigate the impact of competition upon industry inventory a splitting rule specifies how initial industry demand is allocated among competing firms and how any excess demand is allocated among firms with remaining inventory we examine the relation between equilibrium inventory levels and the splitting rule and provide conditions under which there is a unique equilibrium our most general result is that if all excess demand is reallocated i e there is perfect substitutability then competition never leads to a decrease in industry inventory

a time series framework for supply chain inventory management we consider a supply chain in which the underlying demand process can be described in a linear state space form inventory is managed at various points of the chain members based on local information that each member observes and continuously updates the key feature of our model is that it takes into account the ability of the members to observe subsets of the underlying state vector and adopt their forecasting and replenishment policies accordingly this enables us to model situations in which the members are privy to certain explanatory variables of the demand with the latter possibly evolving according to a vector autoregressive time series for each member we identify an associated demand evolution model for which we propose an adaptive inventory replenishment policy that utilizes the kalman filter technique we then provide a simple methodology for assessing the benefits of various types of information sharing agreements between members of the supply chain we also discuss inventory positioning and cost performance assessment in the supply chain our performance metrics and inventory target levels are usually presented in matrix forms allowing them to accommodate a relatively large spectrum of linear demand models and making them simple to implement several illustrations for possible applications of our models are provided

reputation and imperfect information abstract a common observation in the informal literature of economics and elsewhere is that is multistage games players may seek early in the game to acquire a reputation for being tough or benevolent or something else but this phenomenon is not observed in some formal game theoretic analyses of finite games such as selten s finitely repeated chain store game or in the finitely repeated prisoners dilemma we reexamine selten s model adding to it a small amount of imperfect or incomplete information about players payoffs and we find that this addition is sufficient to give rise to the reputation effect that one intuitively expects

stochastic linear programming games with concave preferences abstract we study stochastic linear programming games a class of stochastic cooperative games whose payoffs under any realization of uncertainty are determined by a specially structured linear program these games can model a variety of settings including inventory centralization and cooperative network fortification we focus on the core of these games under an allocation scheme that determines how payoffs are distributed before the uncertainty is realized and allows for arbitrarily different distributions for each realization of the uncertainty assuming that each player s preferences over random payoffs are represented by a concave monetary utility functional we prove that these games have a nonempty core furthermore by establishing a connection between stochastic linear programming games linear programming games and linear semi infinite programming games we show that an allocation in the core can be computed efficiently under some circumstances

seasonality aggregation and the testing of the production smoothing hypothesis one of the leading hypotheses concerning the dynamics of production over time is the production smoothing hypothesis given a planning horizon which spans a number of production periods the firm need not produce in each period an amount equal to expected sales rather resorting to inventory accumulation and liquidation the firm may follow a production plan temporally smoother than the path of demand if firms faced with convex cost functions chose to smooth the rate of output in order to minimize costs one would expect to observe that the rate of output would vary less than the rate of sales with variations in inventory stocks absorbing some of the fluctuations in sales recently work on the testing of the production smoothing hypothesis has cast doubt on its empirical validity the evidence presented by alan blinder seems to indicate that the variance of production exceeds that of sales in seven out of eight two digit retail industries 1981 and in eighteen out of twenty two digit manufacturing industries 1983 and 1986 the purpose of this paper then is to examine the validity of such tests when seasonally adjusted aggregated data are used the evidence presented show that the relative size of the variances of the seasonally adjusted production and sales does not provide valid tests of the production smoothing hypothesis in addition aggregating over firms where the seasonal patterns differ may also distort tests of production smoothing blinder realized that the use of seasonally adjusted data may not provide an adequate test of the hypothesis stating had they been available i would have preferred to use data that were not seasonally adjusted since the production smoothing model presumably applies to seasonal fluctuations in sales however such data are not available 1983 fn 19 in this paper i focus on the cement industry because the unadjusted disaggregated data are available for the direct testing of the conjecture that aggregate seasonally adjusted data mask production smoothing phenomenon aggregate monthly data on five other industries will also be examined

stochastic programming for decentralized newsvendor with transshipment abstract this paper discusses a family of two stage decentralized inventory problems using a unifying framework taxonomy depicted as a multilevel graph this framework allows us to model and link different problems of competing retailers who independently procure inventory in response to uncertain demand and anticipated inventory decisions of other retailers in this family of problems in the ex post stage the retailers exercise recourse actions in response to the realized demand and competitors chosen procurement levels for example retailers could coordinate inventory transshipment to satisfy shortage with overage based on profit sharing agreements our framework provides a unifying parsimonious view using a single methodological prism for a variety of problems equally importantly as recourse options are laid out our framework clarifies and contributes a modeling connection between problems in a clear taxonomy of models this unifying perspective explicitly links work that appeared in isolation and offers future research directions

the stabilizing effect of inventory in supply chains this paper presents a hierarchical model framework for the analysis of the stabilizing effect of inventories in multiechelon manufacturing distribution supply chains this framework is used to compare the variance of demand to the variance of replenishment orders at different echelons of the system e g retailer wholesaler empirical data and experience with management games suggest that in most industries inventory management policies can have a destabilizing effect by increasing the volatility of demand as it passes up through the chain the bullwhip effect our model helps to explain these observations and indicates mechanisms that can promote stabilization the analysis results also define sufficient conditions for the existence of stabilization and relate these conditions to the optimality of myopic control policies

why is production more volatile than sales theory and evidence on the stockout avoidance motive for inventory holding this paper argues that the macroeconomically interesting features of inventory behavior are well captured by a model in which firms face only demand uncertainty with a nonnegativity constraint on inventories empirical implications of the stockout avoidance model of inventory behavior are derived and then tested on disaggregated automobile industry data the results largely support the model though they suggest a small role for production smoothing as well subsidiary evidence on the relative variance of demand and cost shocks suggests that demand shocks are indeed more important

toward the fair sharing of profit in a supply network formation abstract the design of a supply chain network can be interpreted as a coalition formation problem in a cooperative game theory and formulated as a linear production game lpg the companies that are members of the optimal coalition share their manufacturing assets and resources to produce a set of end products and globally maximize their profits by selling them in a market this paper investigates the possibility of combining the requirement of coalition stability with a fair allocation of profits to the participants it is shown that in general the purely competitive allocation mechanism does not exhibit the property of fairness a technique is proposed to construct a stable and fair allocation system when the core of the game does not exclusively contain a set of competitive allocations

migration proof tiebout equilibrium existence and asymptotic efficiency abstract tiebout s basic claim was that when public goods are local competition between jurisdictions solves the free riding problem in the sense that equilibria exist and are always pareto efficient unfortunately the literature does not quite support this conjecture for finite economies one must choose between notions of tiebout equilibrium which are pareto optimal but which may be empty or which are nonempty but may be inefficient this paper introduces a new equilibrium notion called migration proof tiebout equilibrium which we argue is a natural refinement of nash equilibrium for a multijurisdictional environment we show for sufficiently large economies with homogeneous consumers such an equilibrium always exists is unique and is asymptotically pareto efficient

a three stage model for a decentralized distribution system of retailers we present and study a three stage model of a decentralized distribution system consisting ofn retailers each of whom faces a stochastic demand for an identical product in the first stage before the demand is realized each retailer independently orders her initial inventory in the second stage after the demand is realized each retailer decides how much of her residual supply demand she wants to share with the other retailers in the third stage residual inventories are transshipped to meet residual demands and an additional profit is allocated our model is an extension of the two stage model of anupindi et al abz 2001 which implicitly assumes that all residuals enter the transshipment stage we show however that allocation rules in the third stage based on dual solutions which were used in the abz model may induce the retailers to hold back some of their residual supply demand in general we study the effect of implementing various allocations rules in the third stage on the values of the residual supply demand the retailers are willing to share with others in the second stage and the trade off involved in achieving an optimal solution for the corresponding centralized system

stability and monotonicity in newsvendor situations this study considers a supply chain that consists of n retailers each of them facing a newsvendor problem and a supplier groups of retailers might increase their expected joint profit by joint ordering and inventory centralization however we assume that the retailers impose some level of stock that should be dedicated to them in this situation we show that the associated cooperative game has a non empty core afterwards we concentrate on a dynamic situation where several model cost parameters and the retailers dedicated stock levels can change we investigate how the profit division might be affected by these changes we focus on four monotonicity properties we identify several classes of games with retailers where some of the monotonicity properties hold moreover we show that pairs of cooperative games associated with newsvendor situations do not necessarily satisfy these properties in general when changes in dedicated stock levels are in concern

analysis of the bullwhip effect in a multiproduct setting with interdependent demands the bullwhip effect has been extensively studied primarily based on the analysis of various single product models with a few exceptions we extend the single product analysis to the multiproduct setting of interdependent demand streams with auto correlation and cross product correlation as well as contemporaneous correlation across forecasting errors we find that interdependency between demand streams plays a critical role in determining the existence and magnitude of the bullwhip effect specifically we consider two operating environments a the firm orders product specific materials so that the ordering decision is based on the product level and b the firm orders generic materials so that the order decision is based on the category level we show that even with demand pooling a firm operating at the category level can experience a larger bullwhip effect and a larger order variance under certain conditions that depend on the number of products in the category and the demand dependencies

the production and inventory behavior of the american automobile industry understanding inventory movements is central to an understanding of business cycles this paper presents an empirical study of the behavior of inventories in the automobile industry it finds that inventory behavior is well explained by the assumption of intertemporal optimization with rational expectations the underlying cost structure appears to have substantial costs of changing production as well as substantial costs of being away from target inventory thelatter being a function of current sales given this cost structure whether inventory behavior is stabilizing or destabilizing depends on the characteristics of the demand process in the automobile industry inventory behavior is destabilizing the variance of production is larger than the variance of sales

a capacitated production inventory model with periodic demand for a single product single stage capacitated production inventory model with stochastic periodic cyclic demand we find the optimal policy and characterize some of its properties we study the finite horizon the discounted infinite horizon and the infinite horizon average cases a simulation based optimization method is provided to compute the optimal parameters based on a numerical study several insights into the model are also provided

information sharing and order variability control under a generalized demand model the value of information sharing and how it could address the bullwhip effect have been the subject of studies in the literature most of these studies used different forms of demand models assuming that no order smoothing was used by the retailer and that the supplier has full knowledge of the retailer s demand model and order policy in this paper we contribute to the literature by starting with a most general demand model coupled with a smoothing policy for order variability control in addition we do not require that the supplier has full knowledge of the retailer s demand model and order policy but instead let the retailer share its projected future orders and freely revise them as the retailer sees fit under such a setting we first obtain a unifying formula for the magnitude of the bullwhip effect the formula indicates that it is the forecast correlation over the exposure period as a whole that determines the magnitude of the bullwhip effect we then quantify the value of information sharing and generalize the existing results in the literature finally we explore the optimal smoothing parameters that could benefit the total supply chain the resulting optimal policy resembles the postponement strategy we find that information sharing together with order postponement improves the supply chain performance even though the order variability may amplify in some cases

small sample uncertainty aspects in relation to bullwhip effect measurement abstract the bullwhip effect as a concept has been known for almost half a century starting with the forrester effect the bullwhip effect is allegedly observed in many supply chains and it is generally accepted as a potential malice despite this the bullwhip effect still seems to be first and foremost a conceptual phenomenon some even simply denies that the phenomenon exists at all in practice this of course makes it important to perform measurements because only what gets measured gets done as the saying goes in analytics few measurements are reported in the literature however typically based on standard statistical assumptions in the case of a standard measurement of the bullwhip effect independence amongst the participating variables are required amongst others but this is definitely known not to be perfectly true if any systematic control at all have taken place in the supply chain this paper analyses the bullwhip measurement implications in case the standard test assumptions are violated and illustrates how to improve on the testing setup this is further done with a special emphasis on the unavoidable small sample aspects relating to such measurement in practice which typically renders all statistical asymptotic or robust arguments quite unusable it is shown how h 0 95 confidence test intervals still easily can be obtained numerically in such cases

inventory control in a fluctuating demand environment we present an inventory model where the demand rate varies with an underlying state of the world variable this variable can represent economic fluctuations or stages in the product life cycle for example we derive some basic characteristics of optimal policies and develop algorithms for computing them in addition we show that certain monotonicity patterns in the problem data are reflected in the optimal policies

information distortion in a supply chain the bullwhip effect this article originally appeared in management science april 1997 volume 43 number 4 pp 546 558 published by the institute of management sciences consider a series of companies in a supply chain each of whom orders from its immediate upstream member in this setting inbound orders from a downstream member serve as a valuable informational input to upstream production and inventory decisions this paper claims that the information transferred in the form of orders tends to be distorted and can misguide upstream members in their inventory and production decisions in particular the variance of orders may be larger than that of sales and distortion tends to increase as one moves upstream a phenomenon termed bullwhip effect this paper analyzes four sources of the bullwhip effect demand signal processing rationing game order batching and price variations actions that can be taken to mitigate the detrimental impact of this distortion are also discussed

the variability of aggregate demand with s s inventory policies this paper develops a general theory of the aggregate implications of s s inventory policies it is shown that s s policies add to the variability of demand with the variance of orders exceeding the variance of sales overall the s s theory contradicts the widely held notion that retail inventories act as a buffer protecting manufacturers from fluctuating sales in 1951 arrow harris and marschak 3 introduced the s s form of inventory policy the policies are designed for retailers of finished goods who face economies of scale when placing orders with their suppliers to pursue an s s inventory policy the retailer establishes a lower stock point s and an upper stock point s no order is placed until inventories fall to s or below whereupon they are restored to the maximum of s a general proof of the optimality of these s s inventory policies was provided by scarf 13 at the microeconomic level the model has been extensively investigated formulae are available to compute optimal policies e g ehrhardt 6 and these policies are xidely used in industry e g schwartz ed 14 in addition the model has been extended to increasingly complex demand environments e g karlin and fabens 11 in contrast little is known about the macroeconomic implications of s s policies several recent papers have begun to correct this deficiency akerlof has suggested that pursuit of constant threshold money holding policies of the s s variety might be responsible for the observed low short run income elasticity of the demand for money akerlof 1 and akerlof and milbourne 2 in the operations research literature ehrhardt schultz and wagner 7 analyzed the demand environment of a wholesaler supplying several retailers they required that the distinct retailers have independent sales ruling out the analysis of common factors in sales finally simulation results of blinder 4 suggested a role for the s s model in understanding retail sector inventories however the theoretical difficulties with the model remained unresolved blinder commented if firms have a technology that makes the s s rule optimal aggregation across firms is inherently difficult indeed it is precisely this difficulty which has prevented the s s model from being used in empirical work to date blinder 4 p 459 in this paper we present a general theory of the aggregate implications of s s policies our central finding is that s s policies add to the variability of demand with the variance of orders exceeding the variance of sales this result holds even in the presence of common factors in retail sales in addition a close connection

trade inventories and s s the paper presents empirical tests of the s s model of inventory behavior using aggregate retail trade data estimation and testing are based on the probability distributions of inventories derived by caplin 1985 the excess volatility of retailers demand over their consumers demand and the forgetfulness of inventories under s s are emphasized test results indicate that the time series properties of deliveries and sales are consistent with s s and not a quadratic cost model finally when autoregressions of inventories are given an s s rather than a stock adjustment interpretation traditional empirical problems such as low speeds of adjustment are explained

the bullwhip effect progress trends and directions the bullwhip effect refers to the phenomenon where order variability increases as the orders move upstream in the supply chain this paper provides a review of the bullwhip literature which adopts empirical experimental and analytical methodologies early econometric evidence of bullwhip is highlighted findings from empirical and experimental research are compared with analytical and simulation results assumptions and approximations for modelling the bullwhip effect in terms of demand forecast delay replenishment policy and coordination strategy are considered we identify recent research trends and future research directions concerned with supply chain structure product type price competition and sustainability

order variability in perishable product supply chains abstract empirical research has shown that the degree of order variability in supply chains is significantly influenced by product and industry specific factors this paper analyzes the impact of perishability on order variability and the bullwhip effect in supply chains we decompose the ordering process of a retailer into a sales and an outdating process and quantify their short and long term variability and correlation we find differences to non perishable product supply chains driven by the impact of the inventory depletion policy stock out management and retailers service level requirement these three factors significantly affect the retailer s order variability and thus the decision making process and the profitability of the upstream supply stage for the majority of instances the perishable nature of a product results in the ordering process having a lower variability than the demand process only when inventory depletion is dominated by last in first out in high service level environments variability amplification can be observed we propose a dynamic ordering policy for the upstream supply stage taking into account negative correlation of retailer orders between periods this dynamic policy may lead to substantial performance improvements in a sensitivity analysis we investigate the impact of shelf life lead time and demand correlation

optimal joint inventory and transshipment control under uncertain capacity in this paper we address the optimal joint control of inventory and transshipment for a firm that produces in two locations and faces capacity uncertainty capacity uncertainty e g due to downtime quality problems yield etc is a common feature of many production systems but its effects have not been explored in the context of a firm that has multiple production facilities we first characterize the optimal production and transshipment policies and show that uncertain capacity leads the firm to ration the inventory that is available for transshipment to the other location and characterize the structure of this rationing policy then we characterize the optimal production policies at both locations which are defined by state dependent produce up to thresholds we also describe sensitivity of the optimal production and transshipment policies to problem parameters and in particular explain how uncertain capacity can lead to counterintuitive behavior such as produce up to limits decreasing for locations that face stochastically higher demand we finally explore through a numerical study when the optimal policy is most likely to yield significant benefits compared to simple policies

buying a home with a resale value location location location we develop a dynamic multiregion model where a household s choice of housing location depends on its current wealth and its current type and involves both consumption and investment considerations the relative strength of the consumption motive and the investment motive determines the equilibrium pattern of residential sorting a strong investment consumption motive implies sorting according to household type wealth the model predicts that large house price fluctuations are associated with a low degree of sorting by type this prediction is consistent with evidence from us metropolitan areas when income education and age are used as proxies for household type

destocking the bullwhip effect and the credit crisis empirical modeling of supply chain dynamics in this paper we analyze the strong sales dip observed in the manufacturing industry at the end of 2008 following the bankruptcy of lehman brothers and the subsequent collapse of the financial world we suggest that firms desire to retain liquidity during these times prompted a reaction characterized by the reduction of working capital which materialized as a synchronized reduction in target inventory levels across industries we hypothesize that such a reaction effectively acted as an endogenous shock to supply chains ultimately resulting in the bullwhip effect kind of demand dynamics observed to test this proposition we develop a system dynamics model that explicitly takes into account structural operational and behavioral parameters of supply chains aggregated at an echelon level we calibrate the model for use in 4 different business units of a major chemical company in the netherlands all situated 4 5 levels upstream from consumer demands in their respective supply chains we show that the model gives a very good historical fit of the sales developments during the period following the lehman collapse we test the model s robustness to behavioral parameter estimation errors through sensitivity analysis and the de stocking hypothesis against an alternative model finally we observe that the empirical data is aligned with experimental observations regarding human behavioral mechanisms concerning target adjustment times

capacity restrictions and supply chain performance modelling and analysing load dependent lead times abstract several studies have reported that capacitated supply chains may benefit from an improved dynamic performance as compared to unconstrained ones this occurs as a consequence of the capacity limit acting as a production smoothing filter in this research the relationship between capacity restrictions and the operational performance of supply chains is investigated from a novel perspective i e we assume that the influence of capacity constraints on lead times depends on the supply chain s responsiveness under these circumstances the experiments show that there is a negative effect of capacity constraints on supply chain performance both in terms of process efficiency internal and customer satisfaction external nonetheless the magnitude of this impact greatly depends on the responsiveness of the firm market conditions and adopted policies for inventory management more specifically the combination of tight capacity restrictions and low responsiveness significantly contributes to decrease supply chain performance which may be very damaging for the dynamic behavior of the system in this sense efficient capacity planning proves to be essential to prevent the supply chain from entering into a vicious circle

information transmission and the bullwhip effect an empirical investigation the bullwhip effect is the amplification of demand variability along a supply chain a company bullwhips if it purchases from suppliers more variably than it sells to customers such bullwhips amplifications of demand variability can lead to mismatches between demand and production and hence to lower supply chain efficiency we investigate the bullwhip effect in a sample of 4 689 public u s companies over 1974 2008 overall about two thirds of firms bullwhip the sample s mean and median bullwhips both significantly positive respectively measure 15 8 and 6 7 of total demand variability put another way the mean quarterly standard deviation of upstream orders exceeds that of demand by 20 million we decompose the bullwhip by information transmission lead time estimating the bullwhip s information lead time components with a two stage estimator we find that demand signals firms observe with more than three quarters notice drive 30 of the bullwhip and those firms observe with less than one quarter s notice drive 51 from 1974 1994 to 1995 2008 our sample s mean bullwhip dropped by a third this paper was accepted by christian terwiesch operations management

inventories and the volatility of production a stylized fact associated with inventory behavior is that the variance of production exceeds the variance of sales this paper presents a model of production decisions with demand uncertainty that incorporates no nnegativity constraints on inventories even with no productivity shocks optimal behavior by the firm is consistent with this stylized fact either if demand exhibits positive serial correlation or if the firm can backlog excess demand the reason is that a demand shock affects both the actual inventory level given unchanged production and the desired level production must replenish the stock and adjust to the new desired level copyright 1987 by american economic association

cooperation between multiple news vendors with transshipments we study a situation with n retailers each of them facing a news vendor problem i e selling to customers over a finite period of time product with a short life cycle such as fashion groups of retailers might improve their expected joint profit by coordinating their orders followed by transshipments after demand realization is known we analyze these situations by defining a cooperative game called a general news vendor game for such a situation with n retailers we concentrate on whether it makes sense to cooperate by studying properties of general news vendor games our main result states that general news vendor games have non empty cores

an empirically simulated investigation of the impact of demand forecasting on the bullwhip effect evidence from u s auto industry this study empirically examines the impacts of three major aspects of demand forecasting on the magnitude of the bullwhip effect three research questions are addressed to investigate the association between 1 forecast accuracy 2 aggregate forecasting and 3 responsive forecasting and the bullwhip effect using forecasted demand generated from popular time series forecasting models and real life demand data the study investigates the relationship between the forecasted results and the consequential bullwhip effect the findings show that the forecasting methods used lead to the variation of the bullwhip effect moreover the lead time reduction and the stable demand forecast are beneficial to reduce the bullwhip effect however our empirical results differ from previous findings in two ways i improving forecast accuracy does not necessarily reduce the bullwhip effect and ii aggregate forecasting does not always reduce the bullwhip effect

managing supply chain demand variability with scheduled ordering policies this paper studies supply chain demand variability in a model with one supplier and n retailers that face stochastic demand retailers implement scheduled ordering policies orders occur at fixed intervals and are equal to some multiple of a fixed batch size a method is presented that exactly evaluates costs previous research demonstrates that the supplier s demand variance declines as the retailers order intervals are balanced i e the same number of retailers order each period this research shows that the supplier s demand variance will generally decline as the retailers order interval is lengthened or as their batch size is increased lower supplier demand variance can certainly lead to lower inventory at the supplier this paper finds that reducing supplier demand variance with scheduled ordering policies can also lower total supply chain costs

strong tiebout equilibrium under restricted preferences domain abstract we investigate the existence and give a partial characterization of a strong tiebout equilibrium which consists of an endogenously formed partition of the individuals into disjoint jurisdictions with each jurisdiction producing and financing its own public goods and moreover there exists no group of individuals who can all benefit by establishing their own community in particular no single individual finds it desirable to migrate from his equilibrium jurisdiction the existence proof makes use of the notion of consecutive games which we introduce and show that for such games there always exists a partition with a nonempty core

vertical integration with endogenous contract leadership stability and fair profit allocation abstract this paper studies vertical integration in serial supply chains with a wholesale price contract we consider a business environment where the contracting leader may be endogenously changed before and after forming the integration a cooperative game is formulated to normatively analyze the stable and fair profit allocations under the grand coalition in such an environment our main result demonstrates that vertical integration is stable when all members are pessimistic in the sense that they are sure that they will not become the contracting leader if they deviate from the grand coalition we find that in this case the grand coalition s profit must be allocated more to the retailer and the members with higher costs nevertheless we also show the conditions under which the upstream manufacturer can have strong power as in traditional supply chains

supply chain decision making will shorter cycle times and shared point of sale information necessarily help using a simulated supply chain experiment based on the well known beer game we examine how changes in order and delivery cycles availability of shared point of sale pos information and the pattern of customer demand affect supply chain efficiency we find that speeding up cycle time is beneficial but the sharing of pos information is not necessarily so whether or not the sharing of pos information is beneficial depends on the nature of the demand pattern represented by the pos information if the demand pattern conveys continual change in ultimate downstream customer demand as does an s shaped demand pattern the pos information can distract the upstream decision maker from what is perhaps more immediately relevant information orders placed by the proximate downstream agent and the supply line

quantifying the bullwhip effect using two echelon data a cross industry empirical investigation the bullwhip effect denotes the phenomenon whereby demand variability is amplified from a downstream site buyer to an upstream site supplier in the supply chain this paper contributes to the literature that empirically investigates the bullwhip effect by providing new evidence regarding its prevalence and magnitude in contrast to previous work we use a two echelon approach which allows us to observe variations at both the upstream and the downstream sites by drawing on a financial accounting standard regarding information disclosure about major customers we are able to link 5494 buyers and suppliers in the u s between 1976 and 2009 we merge this information with quarterly financial accounting data to form a sample of 14 933 buyer supplier dyad observations we correct for sample selection bias using propensity score matching and estimate the average bullwhip effect in our sample to be 1 90 i e 90 demand variability amplification between echelons a significant bullwhip effect is observed across industries mining manufacturing wholesale and retail and is supported by several robustness checks we investigate and discuss how these results can be generalized beyond our sample

a critique of tiebout s theory of local public expenditures the last section of this paper presents a rigorous version of tiebout s theory of local public goods it is shown that equilibria exist and are pareto optimal this rigorous theory follows closely the more rigorous part of tiebout s work this rigorous theory makes a number of very special assumptions which make local public goods essentially private the body of this paper presents a series of examples which show that if one tries to generalize the rigorous version of tiebout s theory in a number of interesting directions then equilibria may no longer exist or may not be pareto optimal the conclusion is that tiebout s idea does not lead to a satisfactory general theory of local public goods the goal of this paper is to point out that tiebout s notion of equilibrium with local governments does not have the nice properties of general competitive equilibrium except under very restrictive assumptions tiebout 39 suggested that there are competitive forces which tend to make local governments allocate resources in a pareto optimal fashion consumers choose to live in those towns with the mix of taxes and public goods they prefer local governments choose this mix so as to attract inhabitants this idea may seem intriguing for it suggests that the invisible hand solves an important part of samuelson s perplexing public goods problem 32 tiebout in fact makes an argument which is nearly rigorous i give a rigorous version of his argument at the end of the paper however in this rigorous version so many restrictive assumptions are made that public goods become essentially private in the body of the paper i give a series of examples with which i try to convince the reader that one is forced to adopt tiebout s restrictive assumptions the idea is that if one changes any of his assumptions then either equilibria may not exist or may not be pareto optimal my examples are presented in the context of a general class of tiebout models i consider several subclasses one of which is the special case considered by tiebout in each of the subclasses except that considered by tiebout i give a counterexample either to the existence of equilibrium or to its pareto optimality the subclasses are so chosen that the difficulties they reveal would be shared by any reasonable tiebout model which differed from his special case i believe that my examples controvert tiebout s suggestion 39 last paragraph that his theory compares favorably with competitive equilibrium theory most of the examples in this paper have already appeared in the literature i cite related work as i go along what is new here is that i assemble the examples in a unified argument

the bullwhip effect on inventory a perspective on information quality abstractin recent years there has been a vast increase in the quantity of information shared across supply chain we investigate how the timeliness and accuracy of information quality affect the value of information sharing we use the inventory bullwhip effect bwe to measure the value of information sharing in a two level supply chain consisting of one retailer and one manufacturer the retailer faces a price sensitive demand and the price is an ar 1 process our study shows if customer demand and retailer s immediate order are delayed using retailer s historical order quantity to forecast can decrease manufacturer s bwe if information errors happen during delivery and utilization information sharing is not always valuable for the manufacturer sometimes no information sharing can decrease much more of bwe if information errors occur when the retailer collects demand information value of information sharing is more significant than when there are no information errors

global dual sourcing and order smoothing the impact of capacity and lead times after decades of offshoring production across the world companies are rethinking their global networks local sourcing is receiving more attention but it remains challenging to balance the offshore sourcing cost advantage against the increased inventories because of its longer lead time and against the cost and volume flexibility of each source s capacity to guide strategic allocation in this global network decision this paper establishes reasonably simple prescriptions that capture the key drivers we adopt a conventional discrete time inventory model with a linear control rule that smoothes orders and allows an exact and analytically tractable analysis of single and dual sourcing policies under normal demand distinguishing features of our model are that it captures each source s lead time capacity cost and flexibility to work overtime we use lagrange s inversion theorem to provide exact and simple square root bound formulae for the strategic sourcing allocations and the value of dual sourcing the formulae provide structural insight on the impact of financial operational and demand parameters and a starting point for quantitative decision making we investigate the robustness of our results by comparing the smoothing policy with existing single and dual sourcing models in a simulation study that relaxes model assumptions this paper was accepted by yossi aviv operations management

the tiebout model bring back the entrepreneurs several recent papers in the literature have reformulltlated the nature of equilibrium in ifiebout mo lels by alssliuim ing an exogenous number of communities inflexible commullity l ou alaries anti in pirticular inactive lantlowners and developers ihis paper argues that these assumptions are unwarranted and resul1t iin in eterminate solutions and incorrect analyses determinate lon1g run1 solutions require equilibrium in intercommui land markets which in turn require giving lantlowners and or entrepreneurial leveloelers an active role in the models the role of politics in these models and its juxtaposition with entrepreneurial activities are also analyzed

capacity sharing between competitors market competition may lead to mismatch between supply and demand that is overpricing may give rise to underselling and underpricing may yield stockout capacity sharing is a common practice to

optimal centralized ordering policies in multi echelon inventory systems with correlated demands this paper treats a depot warehouse system in which demand occurs at the warehouse or retail level this work differs from a number of other studies in that we allow item demands to be correlated both across warehouses and also correlated in time our motivation for this generalization arises from our experience with an actual system of this type used by a major national producer and distributor of consumer products we observed both high correlations between successive monthly demands around 0 7 and correlations between demands for an item at different locations also about 0 7 in a given time period we derive an explicit expression for the optimal safety stock as a function of the level of correlation through time the analysis requires two assumptions 1 the allocation assumption and 2 the equal coefficient of variation assumption similar assumptions have been used by other researchers finally numerical evaluations are included to illustrate the impact of the various magnitudes of correlation

inventory games with permissible delay in payments abstract meca et al 2004 studied a class of inventory games which arise when a group of retailers who observe demand for a common item decide to cooperate and make joint orders with the eoq policy in this paper we extend their model to the situation where retailer s delay in payments is permitted by the supplier we introduce the corresponding inventory game with permissible delay in payments and prove that its core is nonempty then a core allocation rule is proposed which can be reached through population monotonic allocation scheme under this allocation rule the grand coalition is shown to be stable from a farsighted point of view

the production smoothing model is alive and well abstract monthly data in physical units for seven industries are used to examine the production smoothing hypothesis the results strongly support this hypothesis significant effects of expected future sales on current production are found for four industries and the estimated decision equations for all seven industries imply production smoothing behavior the previous negative results appear to be due to the use of data biased against the hypothesis the shipments and inventory data of the department of commerce the paper also shows that sensible results can be obtained from estimating approximations to decision equations as opposed to estimating euler equations

in search of intra industry bullwhips abstract previous research e g cachon et al 2007 has examined the prevalence and magnitude of the bullwhip effect across industries measuring the bullwhip as the ratio of the variance in the stream of orders placed relative to the variance in orders received in some cases surrogates are used for the order measures our contribution is to use the decomposition framework of jin et al 2016a to look intra industry examining whether the bullwhip is created in shipping manufacturing or ordering and exploring whether this varies across industries our analysis is based on monthly industry level u s census bureau data we find and begin to explain significant differences across industries regarding the source of the bullwhip be it in shipping manufacturing and or ordering we also examine how the bullwhip is impacted by the duration and end point of the time aggregation interval our results suggest that some managers may want to shift their reporting period

bullwhip effect measurement and its implications the bullwhip effect or demand information distortion has been a subject of both theoretical and empirical studies in the operations management literature in this paper we develop a simple set of formulas that describe the traditional bullwhip measure as a combined outcome of several important drivers such as finite capacity batch ordering and seasonality our modeling framework is descriptive in nature as it features certain plausible approximations that are commonly employed in practical inventory systems the results are nonetheless compelling and can be used to explain various conflicting observations in previous empirical studies building on the theoretical framework we discuss the managerial implications of the bullwhip measurement we show that the measurement can be completely noninformative about the underlying supply chain cost performance if it is not linked to the operational details such as decision intervals and leadtimes specifically we show that an aggregated measurement over relatively long time periods can mask the operational level bullwhip in addition we show that masking also exists under product or location aggregation in some illustrative cases

setting the right incentives for global planning and operations we study incentive issues seen in a firm performing global planning and manufacturing and local demand management the stochastic demands in local markets are best observed by the regional business units and the firm relies on the business units forecasts for planning of global manufacturing operations we propose a class of performance evaluation schemes that induce the business units to reveal their private demand information truthfully by turning the business units demand revelation game into a potential game with truth telling being a potential maximizer an appealing refinement of nash equilibrium moreover these cooperative performance evaluation schemes satisfy several essential fairness notions after analyzing the characteristics of several performance evaluation schemes in this class we extend our analysis to include the impact of effort on demand

can the production smoothing model of inventory behavior be saved the production smoothing model of inventory behavior has a long and venerable history and theoretical foundations that seem very strong yet certain overwhelming facts seem not only to defy explanation within the production smoothing framework but actually to argue that the basic idea of production smoothing is all wrong most prominent among these is the fact that the variance of detrended production exceeds the variance of detrended sales this paper first documents the stylized facts then it derives the production smoothing model rigorously and explains how the model can be amended to make it consistent with the facts finally it reviews the theoretical and empirical evidence and tries to draw some tentative conclusions

transshipment of inventories among retailers myopic vs farsighted stability the author considers a model of a decentralized distribution system consisting of n retailers selling an identical product retailers face a stochastic demand and must order their initial inventory before this demand is realized after demand realization retailers decide how much of their unsold inventory or unsatisfied demand they want to share with other retailers this is followed by a transshipment of leftover inventories and distribution of the additional profit generated through inventory sharing the author addresses the following issue suppose that the retailers distribute the profit from inventory sharing according to an allocation rule that induces retailers to share their residuals in a way that maximizes the additional profit such as the shapley value but may not belong to the core is it likely that in this framework all retailers will jointly share their residuals and not form subcoalitions previous research has looked at this problem from a myopic viewpoint and concluded that the grand coalition is not stable unlike the prior work the author looks at stability in a farsighted sense that is retailers do not consider only their immediate payoffs but are also concerned with reactions of other retailers to their actions in a symmetric setting with identical additional unit revenues from transshipments generated by all retailers farsighted retailers always maximize their allocations by not defecting from the grand coalition the author also provides conditions when the same is true for nonidentical additional unit revenues

capacitated inventory problems with fixed order costs some optimal policy structure abstract almost 40 years ago h scarf the optimality of s s policies in dynamic inventory problems in k arrow s karlin p suppes eds mathematical models in the social sciences stanford university press stanford 1960 established the optimal s s policy structure for the periodic review inventory problem with fixed ordering costs and no capacity constraint since then the capacitated problem has resisted characterization in the present paper we partially bridge this gap using a generalization of scarf s k convexity we show that the optimal capacitated policy has an s s like structure to do so we divide the parameter space into four regions in two of these regions the optimal policy is completely specified while in the other two it is partially specified we complement these findings with a computational study this study suggests that a still simpler optimal policy structure exists