modeling farm level crop insurance demand with panel data a random effects binomial probit model is applied to data for a panel of kansas wheat farms to examine multiple peril crop insurance demand a theoretical model is developed which suggests inclusion of the moments of both market return and the return to insurance empirical results indicate that the first and second moments of both market return and the returns to insurance are significant the price elasticity of demand is estimated to be 0 65 preseason weather variables when included in the models were not found to be significant failing to support the hypothesis of intertemporal adverse selection

two stage bargaining with coverage extension in a dual labour market abstract this paper studies coverage extension in a simple general equilibrium model with a dual labour market the union sector is characterized by two stage bargaining whereas the firms set wages in the non union sector in this model firms and unions of the union sector have a commonality of interest in extending coverage of a minimum wage to the non union sector furthermore the union sector does not seek to increase the non union wage to a level above the market clearing wage in fact it is optimal for the union sector to impose a market clearing wage on the non union sector finally coverage extension increases welfare in this model

developing variable unit structure premium rate differentials in crop insurance federal crop insurance programs offer producers the option of insuring farm units individually or as an aggregate unit existing programs offer a fixed 10 discount for most growers taking coverage at the aggregate level this article describes an analysis of risk changes when units are aggregated the methods described here which base unit aggregation discounts on observable farm characteristics are approved for implementation into the federal crop insurance program

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

evolution of the economics of agricultural policy agricultural economists helped develop farm programs to respond to the dire economic situation of the 1920s and 1930s some early authors appreciated that such policies created problems in markets for commodities and inputs over time our understanding of agricultural issues and policies has deepened through the application of improved models and tools of analysis to more extensive data we have developed better answers to old questions and have responded to changing policy instruments market contexts and policy concerns this article traces the evolution of our deepening economic understanding of the causes and consequences of agricultural policy

profit sharing capital formation and the nairu this paper reconsiders the impact of different remuneration systems on aggregate employment contrary to common wisdom on this topic we show that the switch from a fixed wage economy to a share economy results in lower aggregate unemployment an additional innovation of this paper is the endogeneity of the capital stock decision of the firm which enables us to assess and reject the common disincentive to invest criticism of a share economy

efficiency wages and local wage bargaining in the literature on wage drift it is often argued that strikes or work to rule practices are used to force employers to pay a wage rate that exceeds the contract wage here we introduce the efficiency wage argument as a foundation for bargaining about wage drift contrary to the view in most bargaining models where firms and unions struggle to divide a fixed pie given employment we take the relation between wages and revenues explicitly into account the implications for wages and employment appear to differ not only with respect to the order of magnitude but also in a qualitative sense

input demand under yield and revenue insurance previous studies disagree on the effects of insurance on fertilizer application rates the effect of increased fertilizer on the probability of low yields primarily determines whether fertilizer and insurance are substitutes or complements we estimate conditional distributions of corn yields to determine if the technical relationship between yields and fertilizer supports the hypothesis that insurance increases optimal application rates our results indicate no support for this hypothesis at all nitrogen fertilizer rates and reasonable levels of risk aversion nitrogen fertilizer and insurance are substitutes suggesting that those who purchase insurance are likely to decrease nitrogen fertilizer applications

modeling conditional yield densities given the increasing interest in agricultural risk many have sought improved methods to characterize conditional crop yield densities while most have postulated the beta as a flexible alternative to the normal others have chosen nonparametric methods unfortunately yield data tends not to be sufficiently abundant to invalidate many reasonable parametric models this is problematic because conclusions from economic analyses which require estimated conditional yield densities tend not to be invariant to the modeling assumption we propose a semiparametric estimator that because of its theoretical properties and our simulation results enables one to empirically proceed with a higher degree of confidence copyright 2003 oxford university press

analysis of compound bullwhip effect causes abstract this research investigates compound causes of the bullwhip effect bwe by considering an inventory system with multiple price sensitive demand streams joint price and demand dynamics are captured by a vector time series process that incorporates the stochastic co movements in price and demand we study two bwe measures one for each demand stream individually and one for the aggregated demand we show that demand parameters including demand autocorrelation cross correlation and price sensitivity serve as root causes of the bwe we prove that the impact of these parameters on the bwe can be additively decomposed conditions are established under which a pair of simultaneous compound causes may attenuate or dampen the bwe when demand streams are aggregated we derive a pooling factor that quantifies the impact of demand aggregation on order stability when positive the pooling factor corresponds to a synergy effect that captures the gain in the stability of the pooled orders conditions for the existence of the synergy effect are obtained for several special cases involving a zero leadtime we also discuss how our analytical findings can be managerially applied to bullwhip mitigation strategies

providing a measure for bullwhip effect in a two product supply chain with exponential smoothing forecasts abstract in this paper a two product and two echelon supply chain is considered in order to quantify the bullwhip effect demands of the products are correlated and are represented by a first order vector autoregressive model retailer uses order up to ordering policy for replenishment of stocks and utilizes exponential smoothing forecast method to predict demand in lead time period according to the mentioned assumptions an equation is derived for bullwhip effect measurement and then a numerical example is presented for a better perception of the bullwhip effect behavior when the parameters change a comparison of the bullwhip effect measure has been done when two main forecasting methods i e exponential smoothing and moving average are used and empirical results are provided at last a cost analysis is conducted based on shortage and holding cost under different bullwhip effect measures

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

marketing quotas and random yields marginal effects of inframarginal subsidies on peanut supply the u s peanut program restricts domestic sales with poundage quota but allows surplus production to be exported or crushed empirical analysis of north carolina peanut production reveals that the marginal and lower price received by production above quota that is the world price is far more important in determining acreage than is the inframarginal subsidy of the quota support price

avoiding the bullwhip effect using damped trend forecasting and the order up to replenishment policy we study the damped trend forecasting method and its bullwhip generating behaviour when used within the order up to out replenishment policy using z transform transfer functions we determine complete stability criteria for the damped trend forecasting method we show that this forecasting mechanism is stable for a much larger proportion of the parametrical space than is generally acknowledged in the literature we provide a new proof to the known fact that the naive exponential smoothing and holts method forecasting when used inside the out policy will always generate bullwhip for every possible demand process for any lead time further we demonstrate the damped trend out system behaves differently sometimes it will generate bullwhip and sometimes it will not bullwhip avoidance occurs when demand is dominated by low frequency harmonics in some instances in other instances bullwhip avoidance happens when demand is dominated by high frequency harmonics we derive sufficient conditions for when bullwhip will definitely be generated and necessary conditions for when bullwhip may be avoided we verify our analytical findings with a numerical investigation

are crop yields normally distributed the evidence for nonnormality of crop yields is reassessed three methodological problems are identified in typical yield distribution analyses i misspecification of the nonrandom components of yield distributions ii missreporting of statistical significance and iii use of aggregate timeseries ats data to represent farm level yield distributions one or more of these problems infect virtually all evidence against normality to date the positive contribution of the article is a set of principles that must be followed in any valid investigation of yield normality

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

contracting and information sharing under supply chain competition we investigate contracting and information sharing in two competing supply chains each consisting of one manufacturer and one retailer the two supply chains are identical except they may have di

strategic commitments for an optimal capacity decision under asymmetric forecast information we study the important problem of how to assure credible forecast information sharing between a supplier and a manufacturer the supplier is responsible for acquiring the necessary capacity before receiving an order from the manufacturer who possesses private forecast information for her end product we address how different contracts affect the supplier s capacity decision and hence the profitability of the supplier and the manufacturer we fully develop two contracts and provide explicit formulae to enable credible forecast information sharing the first is a nonlinear capacity reservation contract under which the manufacturer agrees to pay a fee to reserve capacity the second is an advance purchase contract under which the manufacturer is induced to place a firm order before the supplier secures the component capacity used to build the end product these contracts serve a strategic role in information sharing the capacity reservation contract enables the supplier to detect the manufacturer s private forecast information while the advance purchase contract enables the manufacturer to signal her forecast information we show that channel coordination is possible even under asymmetric forecast information by combining the advance purchase contract with an appropriate payback agreement through our structural and numerical results we also show that the degree of forecast information asymmetry and the risk adjusted profit margin are two important drivers that determine supply chain efficiency and which contract to adopt

information sharing in supply chains an empirical and theoretical valuation we provide an empirical and theoretical assessment of the value of information sharing in a two stage supply chain the value of downstream sales information to the upstream firm stems from improving upstream order fulfillment forecast accuracy such an improvement can lead to lower safety stock and better service based on the data collected from a consumer packaged goods company we empirically show that if the company includes the downstream sales data to forecast orders the improvement in the mean squared forecast error ranges from 7 1 to 81 1 across all studied products theoretical models in the literature however suggest that the value of information sharing should be zero for over half of our studied products to reconcile the gap between the literature and the empirical observations we develop a new theoretical model whereas the literature assumes that the decision maker strictly adheres to a given inventory policy our model allows him to deviate accounting for private information held by the decision maker yet unobservable to the econometrician this turns out to reconcile our empirical findings with the literature these decision deviations lead to information losses in the order process resulting in a strictly positive value of downstream information sharing furthermore we empirically quantify and show the significance of the value of operations knowledge the value of knowing the downstream replenishment policy this paper was accepted by serguei netessine operations management

crop insurance valuation under alternative yield distributions considerable disagreement exists about the most appropriate characterization of farm level yield distributions yet the economic importance of alternative yield distribution specifications on crop insurance valuation has not been well documented the results of this study demonstrate that large differences in expected payouts from popular crop insurance products can arise solely from the parameterization chosen to represent yield distributions the results suggest that the frequently unexamined yield distribution specification may lead to economically significant errors in crop insurance policy rating and assessment of expected payouts from policies

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

analyzing the effect of the inventory policy on order and inventory variability with linear control theory in this paper we apply linear control theory to study the effect of various inventory policies on order and inventory variability which are key drivers of supply chain performance in particular we study a two echelon supply chain with a stationary demand pattern under the influence of three inventory policies an inventory on hand policy that bases orders on the visible inventory at an installation an installation stock policy that bases orders on the inventory position on hand plus on order inventory at an installation and an echelon stock policy that bases orders on the inventory position at that installation and all downstream installations we prove analytically that the inventory on hand policy is unstable in practical settings confirming analytically what has been observed in experimental settings and in practice we also prove that the installation stock and echelon stock policies are stable and analyze their effect on order and inventory fluctuation specifically we show the general superiority of the echelon stock in our setting and demonstrate analytically the effect of forecasting parameters on order and inventory fluctuations confirming the results in other research

nonparametric estimation of crop yield distributions implications for rating group risk crop insurance contracts we use nonparametric density estimation procedures to evaluate county level crop yield distributions implications for rating area yield crop insurance contracts are discussed the procedures developed are used to measure yield risk and calculate insurance premium rates for wheat and barley in the 1995 96 group risk program

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

an arima supply chain model this paper presents a multistage supply chain model that is based on autoregressive integrated moving average arima time series models given an arima model of consumer demand and the lead times at each stage it is shown that the orders and inventories at each stage are also arima and closed form expressions for these models are given the paper also discusses the causes of the bullwhip effect a phenomenon in which variation in demand produces larger variations in upstream orders and inventory this discussion reveals how different modeling can lead to different insights because they make different assumptions about the cause of the bullwhip effect these observations are used to develop managerial insights about reducing the bullwhip effect

analysis of the bullwhip effect in two parallel supply chains with interacting price sensitive demands abstract this paper offers insights into how the bullwhip effect in two parallel supply chains with interacting price sensitive demands is affected in contrast to the situation of a single product in a serial supply chain in particular this research studies two parallel supply chains each consisting of a manufacturer and a retailer and the external demand for a single product depends on its price and the other s price in a situation in which each price follows a first order autoregressive process in this paper we propose an analytical framework that incorporates two parallel supply chains and we explore their interactions to determine the bullwhip effect we identify the conditions under which the bullwhip effect is amplified or lessened with interacting price sensitive demands relative to the situation without interaction

adverse selection in crop insurance actuarial and asymmetric information incentives adverse selection is often blamed for crop insurance indemnities exceeding premiums plus subsidies however nationwide empirical evidence has been lacking or based on inadequate county level data this article uses nationwide farm level data on corn and soybeans to decompose incentives for participation in u s multiple peril crop insurance into a risk aversion incentive the conventional justification for insurance an actuarial or subsidy incentive reflecting government subsidization and an asymmetric information incentive which reflects farmers information advantage results show that the risk aversion incentive is small farmers participate in crop insurance primarily to receive the subsidy or because of adverse selection possibilities

using cumulative prospect theory to explain anomalous crop insurance coverage choice farmers decisions about how much crop insurance to buy are not generally consistent with expected utility maximization taking into account both marginal risk benefits and marginal subsidy effects suggests that most farmers have chosen lower coverage levels than would be predicted by standard models by modeling financial outcomes as gains and losses cumulative prospect theory offers an alternative framework to perhaps better understand farmers purchase decisions the role of the reference point that defines outcomes as either a gain or a loss the degree of loss aversion curvature of the value function and the probability weighting function in determining optimal crop insurance coverage levels are explored for three representative farms calibrated to 2009 conditions loss aversion and how crop insurance is framed through choice of the reference point are shown to be the key factors that determine whether predictions from prospect theory are consistent with observed crop insurance coverage choices when crop insurance is framed as a tool to manage farm risk then optimal choices under prospect theory are not consistent with observed choices if crop insurance is framed as a stand alone investment where a loss is felt if the indemnity received is less than the premium paid then prospect theory can generate optimal coverage level choices that are largely consistent with observed decisions this result is shown to be robust to changes in parameterizations as long as loss aversion is maintained and if curvature of the value function is accompanied by decision weights that overweight low probability outcomes

sharing demand information in competing supply chains with production diseconomies this paper studies the incentive for vertical information sharing in competing supply chains with production technologies that exhibit diseconomies of scale we consider a model of two supply chains each consisting of one manufacturer selling to one retailer with the retailers engaging in cournot or bertrand competition for cournot retail competition we show that information sharing benefits a supply chain when 1 the production diseconomy is large and 2 either competition is less intense or at least one retailer s information is less accurate a supply chain may become worse off when making its information more accurate or production diseconomy smaller if such an improvement induces the firms in the rival supply chain to cease sharing information for bertrand retail competition we show that information sharing benefits a supply chain when 1 the production diseconomy is large and 2 either competition is less intense or information is more accurate under bertrand competition a manufacturer may be worse off by receiving information which is never the case under cournot competition information sharing in one supply chain triggers a competitive reaction from the other supply chain and this reaction is damaging to the first supply chain under cournot competition but may be beneficial under bertrand competition this paper was accepted by martin lariviere 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

conditions of reverse bullwhip effect in pricing under joint decision of replenishment and pricing abstract a reverse bullwhip effect in pricing rbp occurs when an amplification of price variability takes place moving from the upstream suppliers to the downstream customers in a supply chain in this study we investigate rbp conditions for supply chains where joint replenishment and pricing decisions are made commencing with a single stage supply chain in which a retailer faces a random and price sensitive demand we extend the results to a multi stage supply chain using a leader follower game theoretical framework we discuss rbp conditions for supply chains where newsvendor and continuous review inventory policies are employed and present numerical examples for commonly used demand functions

the impact of information enrichment on the bullwhip effect in supply chains a control engineering perspective this paper examines the beneficial impact of information sharing in multi echelon supply chains we compare a traditional supply chain in which only the first stage in the chain observes end consumer demand and upstream stages have to base their forecasts on incoming orders with an information enriched supply chain where customer demand data e g epos data is shared throughout the chain two types of replenishment rules are analysed order up to out policies and smoothing policies policies used to reduce or dampen variability in the demand for the class of out policies we will show that information sharing helps to reduce the bullwhipeffect variance amplification of ordering quantities in supply chains significantly especially at higher levels in the chain however the bullwhip problem is not completely eliminated and it still increases as one moves up the chain for the smoothing policies we show that information sharing is necessary to reduce order variance at higher levels of the chain the methodology is based on control systems engineering and allows us to gain valuable insights into the dynamic behaviour of supply chain replenishment rules we also introduce acontrolengineering based measure to quantify the variance amplification bullwhip or variance reduction

demand evolution in stochastic inventory systems riskiness increase abstract this paper characterizes demand evolution in the steady state under common inventory policies in a single location stochastic inventory system our results show that downstream demand nonstrictly second degree stochastically dominates upstream orders and the bullwhip effect occurs we provide the link between demand evolution and utility theory for stochastic inventory systems our model is general in that ultimate customer demand follows an arbitrary stationary distribution and the facility may arbitrarily select policy parameters

reverse bullwhip effect in pricing price variability is one of the major causes of the bullwhip effect this paper analyzes the impact of procurement price variability in the upstream of a supply chain on the downstream retail prices procurement prices may fluctuate over time for example when the supply chain players deploy auction type procurement mechanisms or if the prices are dictated in market exchanges a game theory framework is used here to model a serial supply chain sequential price game scenarios are investigated to show that there is an increase in retail price variability and an amplified reverse bullwhip effect on prices rbp under certain demand conditions

the extension and exploitation of the inventory and order based production control system archetype from 1982 to 2015 in 1994 through classic control theory john naim and towill developed the automatic pipeline inventory and order based production control system apiobpcs which extended the original iobpcs archetype developed by towill in 1982 well recognised as a base framework for a production planning and control system due to the prevalence of the two original models in the last three decades in the academic and industrial communities this paper aims to systematically review how the iobpcs archetypes have been adopted exploited and adapted to study the dynamics of individual production planning and control systems and whole supply chains using various databases such as scopus web of science google scholar 111 papers we found that the iobpcs archetypes have been studied regarding the a modification of four inherent policies related to forecasting inventory lead time and pipeline to create a family of models b adoption of the iobpcs family to reduce supply chain dynamics and in particular bullwhip c extension of the iobpcs family to represent different supply chain scenarios such as order book based production control and closed loop processes simulation is the most popular method adopted by researchers and the number of works based on discrete time based methods is greater than those utilising continuous time approaches most studies are conceptual with limited practical applications described future research needs to focus on cost flexibility and sustainability in the context of supply chain dynamics and although there are a few existing studies more analytical approaches are required to gain robust insights into the influence of nonlinear elements on supply chain behaviour also empirical exploitation of the existing models is recommended

valuing agricultural insurance this paper proposes a method for estimating a farmer s stochastic discount factor that is independent of his or her risk preferences and shows that that stochastic discount factor is appropriate for calculating a farmer s willingness to pay for a crop insurance product an empirical example illustrates how production and price data might be combined with returns data to permit econometric estimation of the stochastic discount factor and the implications of those illustrative results are briefly discussed

wage drift and the relevance of centralised wage setting the system of wage setting in the nordic countries is often regarded as highly centralised contributing to considerable real wage flexibility this view has been questioned as sizeable wage drift may offset the effect of central negotiations this paper presents evidence from the four major nordic countries suggesting that there is little or no such offsetting effect yet at central negotiations the institutional system of wage formation may induce nominal rigidities that may prevent wage restraint when there is little room for money wage growth empirical evidence supports the existence of nominal rigidity

nonparametric estimation of crop insurance rates revisited with the crop insurance program becoming the cornerstone of u s agricultural policy recovering accurate rates is of paramount interest lack of yield data presents by far the most fundamental obstacle to recovery of accurate rates thisarticle employsnew methodology to estimate conditional yield densities and derive the insurance rates in our application we find the nonparametric kernel density estimator requires an additional twenty six years of yield data to estimate the shape of the conditional yield dens itiesasaccurately asthe recently developed empirical bayesnonparametric kernel density estimator such methodological improvements can significantly aid in ameliorating the data problem recovering accurate premium ratesis paramount to the actuarial soundness of the crop insurance program a program which hasgained prominence in the overall u s agricultural policy agenda the 1996 federal agricultural improvement and reform fair act signaled a new policy environment under which farmerswould be s to market forces under this policy regime crop insurance remains in some respects one of the only government subsidized income stabilizing mechanisms available to agricultural producers in addition it appears that current political forcesare in the proces sof fashioning crop insurance as the cornerstone of u s agricultural policy consider the 1999 state of the union address in which the president stated

on the stability of supply chains this paper examines the stability of decentralized multistage supply chains under arbitrary demand conditions it looks for intrinsic properties of the inventory replenishment policies that hold for all customer demand processes and for policies with desirable properties it is found that the overall conditions experienced by suppliers several stages removed from the final customer e g the variances of the orders they receive and the inventories they keep depend on the policy much more than on the demand process a policy specific but demand independent upper bound for the order variance amplification factor of any decentralized policy is shown to exist and its formula is presented the bound is always tight for the suppliers at the end of a long chain so that a policy exhibits the bullwhip effect if and only if its bound is greater than 1 a simple necessary condition for bullwhip avoidance is also identified in terms of a policy s gain gain is the marginal change in average inventory induced by a policy when there is a small but sustained change in the demand rate it is shown thatall policies with positive gain produce the bullwhip effect if they do not use future order commitments because manufacturers can reduce costs by operating with positive gain this explains the prevalence of the bullwhip effect a family of commitment based policies that can dynamically maintain any desired inventory level for any demand rate e g achieve positive gain without the bullwhip effect is also presented the family includes just in time strategies as a special case simulation results are used as an illustration

coordinating lead times and safety stocks under autocorrelated demand we consider a supply chain in which orders and lead times are linked endogenously as opposed to assuming lead times are exogenous this assumption is relevant when a retailer s orders are produced by a supplier with finite capacity and replenished when the order is completed the retailer faces demands that are correlated over time either positively or negatively which may for example be induced by a pricing or promotion policy the auto correlation in demand affects the order stream placed by the retailer onto the supplier and this in turn influences the resulting lead times seen by the retailer since these lead times also determine the retailer s orders and its safety stocks which the retailer must set to cover lead time demand there is a mutual dependency between orders and lead times the inclusion of endogenous lead times and autocorrelated demand represents a better fit with real life situations however it poses some additional methodological issues compared to assuming exogenous lead times or stationary demand processes that are independent over time by means of a markov chain analysis and matrix analytic methods we develop a procedure to determine the distribution of lead times and inventories that takes into account the correlation between orders and lead times our analysis shows that negative autocorrelation in demand although more erratic improves both lead time and inventory performance relative to iid demand positive correlation makes matters worse than iid demand due to the endogeneity of lead times these effects are much more pronounced and substantial error may be incurred if this endogeneity is ignored

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

actuarial fairness of crop insurance rates with constant rate relativities increased availability and demand for low deductible crop insurance policies have increased focus on crop insurance rating methods actuarial fairness cannot be achieved if constant multiplicative factors are used to determine how premiums change as coverage levels increase a comparison of premium rates generated by the factors used by the two most popular crop insurance products with those generated by a standard yield distribution shows that the popular insurance products overcharge for low deductible policies in most counties this overpricing may explain why large premium subsidies were required to induce farmers to move from low deductible to high deductible policies beginning in 2001 crop insurance is by far the most popular risk management tool used by the u s crop producers in 2003 the u s crop insurance program insured more than 200 million acres representing more than 37 billion in value with total premium of over 3 14 billion the two most popular crop insurance products are actual production history aph which provides insurance against low yields and crop revenue coverage crc which is a revenue insurance product both of these products offer coverage in 5 increments from 65 to 85 of expected yield or revenue beginning with the 2001 crop year congress greatly increased subsidy levels to induce producers to purchase more insurance coverage producers responded as expected for example only 2 3 of kansas wheat was insured at levels in excess of 65 in 1998 this proportion rose to 71 6 in 2003 this policy change has increased focus on the methods used by the risk management agency rma of usda to set insurance rates at higher coverage levels aph premium rates are calculated by multiplying the premium rate at the 75 coverage level by a rate

measuring imputed cost in the semiconductor equipment supply chain we consider the order fulfillment process of a supplier producing a customized capital good such as production equipment commercial aircraft medical devices or defense systems as is common in these industries prior to receiving a firm purchase order from the customer the supplier receives a series of shared forecasts which are called soft orders facing a stochastic internal manufacturing lead time the supplier must decide at what time to begin the fulfillment of the order this decision requires a trade off between starting too early leading to potential holding or cancellation costs and starting too late leading to potential delay costs we collect detailed data of shared forecasts actual purchase orders production lead times and delivery dates for a supplier buyer dyad in the semiconductor equipment supply chain under the assumption that the supplier acts rationally optimally balancing the cancellation holding and delay costs we are able to estimate the corresponding imputed cost parameters based on the observed data our estimation results reveal that the supplier perceives the cost of cancellation to be about two times higher and the holding costs to be about three times higher than the delay cost in other words the supplier is very conservative when commencing the order fulfillment which undermines the effectiveness of the overall forecast sharing mechanism

local and central wage bargaining the literature on wage bargaining usually considers either central or local wage bargaining an exception is holmlund 1986 throughout most of the unionized part of the private sector in norway wage bargaining takes place on two levels first centrally and then locally in the economic policy debate it has been argued that this system leads to higher wages and lower employment than bargaining on only one level regardless of whether it is central or local see e g skatnland 1983 in this paper i present a model with wage bargaining on two levels and show that in this system the above argument is proved false we focus on an industry with n identical firms which produce one homogeneous product for simplicity the output price and input prices other than wages are considered given on the central level there is a utility maximizing labor union with a quasi concave utility function increasing in the arguments employment l and total wage vv there is a local labor union in each firm we analyze the system during one period say a year wage setting in this period consists of three stages in the first stage the central labor union sets the tariff wage q unilaterally this follows the monopoly model of e g dunlop 1944 and oswald 1985 in the second stage the firms determine the employment l which prevails until the next period in the third and final stage the local union negotiates with the management of the firm about local wage drift the total wage is w q wage drift the assumption that the firms determine employment prior to wage bargaining is used by e g moene 1987 and horn wolinsky 1985 both the central labor union and the firms know how local wage bargaining functions and can therefore perfectly anticipate what the result

insider effects in wage determination abstract the paper attempts to shed new light on the determinants of industry wages by a cross country comparison of wage setting relationships making use of comprehensive and consistent panel data on industries from the early 1960s to the mid 1980s the empirical analysis involves estimations of identically specified industry wage equations for each of five countries sweden norway finland germany and the united states a key finding is that industry wages in the u s are the most responsive to sectoral price and productivity changes by contrast industry wages in the nordic countries are largely unaffected by sectoral conditions the results cast doubt on the competitive model as an accurate characterization of wage setting under decentralization

central wage setting under multiple technological equilibria a mechanism for equilibrium elimination instituting an initial round of centralized wage setting before an ultimate round of decentralized wage bargaining may actually raise employment a general multi equilibrium model is set up with strategic complementarities in the implementation of a new technology through aggregate demand spillovers in this model centralized wage setting to establish an outside option wage which is selectively binding on lo tech firms may achieve the big push to a hi tech general equilibrium with higher employment output wages and profits

influence of the premium subsidy on farmers crop insurance coverage decisions the agricultural risk protection act greatly increased the expected marginal net benefit of farmers buying high coverage crop insurance policies by coupling premium subsidies to coverage level this policy change combined with cross sectional variations in expected marginal net benefits of high coverage policies is used to estimate the role that premium subsidies play in farmers crop insurance decisions we use county data for corn soybeans and wheat to estimate regression equations that are then used to obtain insight into two policy scenarios we first estimate that eventual adoption of actuarially fair incremental premiums combined with current coupled subsidies would increase farmers purchase of high coverage policies by almost 400 percent from 1998 levels across the three crops and two plans of insurance included in the analysis we then estimate that a return to decoupled subsidies would decrease farmers high coverage purchase decisions by an average of 36 percent

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

allocation of cost savings in a three level supply chain with demand information sharing a cooperative game approach we analyze the problem of allocating cost savings from sharing demand information in a three level supply chain with a manufacturer a distributor and a retailer to find a unique allocation scheme we use concepts from cooperative game theory first we analytically compute the expected cost incurred by the manufacturer and then use simulation to obtain expected costs for the distributor and the retailer we construct a three person cooperative game in characteristic function form and derive necessary conditions for the stability of each of five possible coalitions to divide the cost savings between two members or among three supply chain members we use various allocation schemes we present numerical analyses to investigate the impacts of the demand autocorrelation coefficient and the unit holding and shortage costs on the allocation scheme

a pragmatic approach to the design of bullwhip controllers it is well known that forecasting mechanisms can greatly increase bullwhip demand variance amplification of orders as processed by both human and algorithmic decision makers this paper is concerned with the application of the well established apiobpcs decision support system a variant of the order up to rule in such circumstances it has two feedback controls based on the inventory and the orders in pipeline respectively with gains set equal according to the deziel eilon rule there is one feed forward control based on exponential forecasting although this is not a restriction on the application of this system we consider the pragmatic role of apiobpcs in the situation where the echelon decision maker may be handling a wide range of sku s in a non altruistic environment where upmarket information may either be withheld or simply unavailable under such circumstances it has been established via site based studies that the decision makers output the orders reflect a wide range of strategies or maybe ignorance three strategies may be regarded as appropriate i e pass orders along demand smoothing and level scheduling depending on context apiobpcs can be adapted to each of these modus operandi in the first case with the added capability of smoothing the sharp edges with a modicum of inventory variation and in the last case with the advantage of built in trend detection players in non altruistic supply chains must be able to cope with added uncertainties due to lead time variations we show that apiobpcs may be well matched to such situations and is hence copable as well as capable the paper includes recommended parameter settings according to desired decision making policies

characterization of the bullwhip effect in linear time invariant supply chains some formulae and tests the authors analyze the bullwhip effect in multistage decentralized supply chains operated with linear and time invariant inventory management policies the focus is on robustness the supply chain is modeled as a single input single output control system driven by arbitrary customer demands the authors derive robust analytical conditions to predict the presence of the bullwhip effect and bound its magnitude based only on the way inventories are managed these results hold independently of the customer demand the authors also characterize the stream of orders placed at any stage of the chain when the customer demand process is known and ergodic and give an exact formula for the variance of the orders placed this formula generalizes existing results by broadening the class of inventory replenishment policies and customer demand processes to which it applies the authors also show that the bullwhip effect can be mitigated by introducing commitments for future orders into the ordering policies

does a manufacturer benefit from selling to a better forecasting retailer this paper considers a manufacturer selling to a newsvendor retailer that possesses superior demand forecast information we show that the manufacturer s expected profit is convex in the retailer s forecasting accuracy the manufacturer benefits from selling to a better forecasting retailer if and only if the retailer is already a good forecaster if the retailer has poor forecasting capabilities then the manufacturer is hurt as the retailer s forecasting capability improves more generally the manufacturer tends to be hurt benefit by improved retailer forecasting capabilities if the product economics are lucrative poor finally the optimal procurement contract is a quantity discount contract

measuring and avoiding the bullwhip effect a control theoretic approach an important contributory factor to the bullwhip effect i e the variance amplification of order quantities observed in supply chains is the replenishment rule used by supply chain members first the bullwhip effect induced by the use of different forecasting methods in order up to replenishment policies is analysed variance amplification is quantified and we prove that the bullwhip effect is guaranteed in the order up to model irrespective of the forecasting method used thus when production is inflexible and significant costs are incurred by frequently switching production quantities up and down order up to policies may no longer be desirable or even achievable in the second part of the paper a general decision rule is introduced that avoids variance amplification and succeeds in generating smooth ordering patterns even when demand has to be forecasted the methodology is based on control systems engineering and allows important insights to be gained about the dynamic behaviour of replenishment rules