employment adjustment versus hours adjustment is job security desirable firms can adjust to shocks by laying off and hiring workers or by adjusting the hours worked by each worker adjustment of hours provides job security for employed workers adjustment of employment generates higher labor market turnover and thus better job prospects for the unemployed since high turnover lowers the expected cost of being laid off by reducing the expected duration of unemployment there is a strategic complementarity between firms in the provision of job security this gives the possibility of multiple equilibria with different amounts of turnover copyright 1995 by the london school of economics and political science

random yield supply chain with a yield dependent secondary market abstract this paper considers a simple supply chain with one supplier and one retailer where the supplier s production is subject to random yield and the retailer faces uncertain demand there exists a secondary market for acquiring or disposing products by the supplier we study both the centralized and decentralized systems in the decentralized system a no risk sharing contract and a risk sharing minimum commitment contract are analyzed the supply chain with the risk sharing contract is further analyzed with a constant secondary market price and a yield dependent secondary market price we present both the supplier s and the retailer s optimal strategies and provide insights for managers when making decisions under random yield risk and demand uncertainty we find that the secondary market generally has a positive impact on supply chain performance and the actual effect of random yield risk on the supply chain performance depends on cost parameters and supply chain contract settings under certain conditions reducing yield randomness may weaken the double marginalization effect and improve the chain performance from the numerical study we also show that there exists an optimal commitment level for the supply chain

optimal pricing and return policies for perishable commodities this paper considers the pricing decision faced by a producer of a commodity with a short shelf or demand life a hierarchical model is developed and the results of the single period inventory model are used to examine possible pricing and return policies the paper shows that several such policies currently in effect are suboptimal these include those where the manufacturer offers retailers full credit for all unsold goods or where no returns of unsold goods are permitted the paper also demonstrates that a policy whereby a manufacturer offers retailers full credit for a partial return of goods may achieve channel coordination but that the optimal return allowance will be a function of retailer demand therefore such a policy cannot be optimal in a multi retailer environment it is proven however that a pricing and return policy in which a manufacturer offers retailers a partial credit for all unsold goods can achieve channel coordination in a multi retailer environment this article was originally published in marketing science volume 4 issue 2 pages 166 176 in 1985

answering the skeptics yes standard volatility models do provide accurate forecasts a voluminous literature has emerged for modeling the temporal dependencies in financial market volatility using arch and stochastic volatility models while most of these studies have documented highly significant in sample parameter estimates and pronounced intertemporal volatility persistence traditional ex post forecast evaluation criteria suggest that the models provide seemingly poor volatility forecasts contrary to this contention we show that volatility models produce strikingly accurate interdaily forecasts for the latent volatility factor that would be of interest in most financial applications new methods for improved ex post interdaily volatility measurements based on high frequency intradaily data are also discussed

vertical contracts in the video rental industry a large body of theoretical work has explored the channels through which vertical contracts can induce efficiency improvements however it is also important to study vertical contracts empirically in order to gain insight into the relative size of different types of efficiency gains in this paper i empirically analyse a contractual innovation in the vertically separated video rental industry prior to 1998 video stores obtained inventory from movie distributors using simple linear pricing contracts in 1998 revenuesharing contracts were widely adopted i investigate the effect of the introduction of revenue sharing contracts on firms profits and consumer welfare i analyse a new panel data set of home video retailers that includes information on individual retailers contract and inventory choices as well as rentals and contract terms for 246 movie titles and 6137 retailers in the u s during each week of 1998 and 1999 and the first half of 2000 a structural econometric model of firms behaviour is developed that describes the nature of firms contract choices estimates from this model indicate that both upstream and downstream profits increase by 10 under the revenue sharing contract for popular titles for less popular titles the effects can be even larger i also estimate that consumers benefit when revenue sharing contracts are adopted

flexible and risk sharing supply contracts under price uncertainty we study supply contracts for deterministic demand but in an environment of uncertain prices we develop valuation methodologies for different types of supply contracts a time inflexible contract requires the firm to specify not only how many units it will purchase but also the timing of the purchase a time flexible contract allows the firm to specify the purchase amount over a given period of time without specifying the exact time of purchase other than time flexibility the suppliers may offer quantity flexibility to the firm as well i e purchase quantities could be within a prespecified quantity window finally risk sharing features can be incorporated in the contract in terms of the purchase price that the firm eventually pays to a supplier within a prespecified price window the firm pays the realized price but outside of it the firm shares in an agreed way added costs or benefits given the structure of a supply contract we study the firm s decision when to purchase and how many units in each purchase such that the expected net present value of the purchase cost plus inventory holding cost is minimized we discuss optimal purchasing strategies for both time flexible and time inflexible contracts with risk sharing features other interesting results include the analysis of two supplier sourcing environments and the exploitation of quantity flexibility in such contracts our discussion illustrates how time flexibility quantity flexibility supplier selection and risk sharing when carefully exercised can effectively reduce the sourcing cost in environments of price uncertainty

analysis of supply contracts with quantity flexibility this paper explores a class of supply contracts under which a buyer receives discounts for committing to purchases in advance the further in advance the commitment is made the larger the discount as time rolls forward the buyer can increase the order quantities for future periods of the rolling horizon based on updated demand forecast information and inventory status however the buyer pays a higher per unit cost for the incremental units such contracts are used by automobile and contract manufacturers and are quite common in fuel oil and natural gas delivery markets we develop a finite horizon dynamic programming model to characterize the structure of the optimal replenishment strategy for the buyer we present heuristic approaches to calculate the order volume in each period of the rolling horizon finally we numerically evaluate the heuristic approaches and draw some managerial insights based on the findings

an evaluation of volatility forecasting techniques the existing literature contains conflicting evidence regarding the relative quality of stock market volatility forecasts evidence can be found supporting the superiority of relatively complex models including arch class models while there is also evidence supporting the superiority of more simple alternatives these inconsistencies are of particular concern because of the use of and reliance on volatility forecasts in key economic decision making and analysis and in asset option pricing this paper employs daily australian data to examine this issue the results suggest that the arch class of models and a simple regression model provide superior forecasts of volatility however the various model rankings are shown to be sensitive to the error statistic used to assess the accuracy of the forecasts nevertheless a clear message is that volatility forecasting is a notoriously difficult task

optimal strategies for a three level contract farming supply chain with subsidy abstract we consider a three level contract farming supply chain with a risk averse farmer a risk neutral supplier and a risk neutral distributor in which the farmer faces a yield uncertainty and the government offers agricultural subsidy to the farmer the cvar criterion is used to describe the risk averse behavior of the farmer we derive the optimal strategies of the supply chain and perform some sensitivity analysis to investigate the effects of the government subsidy and other factors the results indicate that as the subsidy increases the farmer s total target production increases further analysis shows that the total production increase is mainly from the increased farm size and the farmer s endeavor actually decreases in addition the results indicate that the profits of the supplier and the distributor both increase with respect to the subsidy however the impact of the subsidy on the farmer s profit depends on the farmer s degree of risk averse in particular the impact of the subsidy to the farmer s profit tends to be positive for farmers with high degree of risk averse and the impact tends to be negative for those with low degree of risk averse the sensitivity analysis is also performed for the level of yield uncertainty in term of the standard deviation

a word of caution on calculating market based minimum capital risk requirements this paper demonstrates that the use of garch type models for the calculation of minimum capital risk requirements mcrrs may lead to the production of inaccurate and therefore inefficient capital requirements we show that this inaccuracy stems from the fact that garch models typically overstate the degree of persistence in return volatility a simple modification to the model is found to improve the accuracy of mcrr estimates in both back and out of sample tests given that internal risk management models are currently in widespread usage in some parts of the world most notably the usa and will soon be permitted for ec banks and investment firms we believe that our paper should serve as a valuable caution to risk management practitioners who are using or intend to use this popular class of models

volatility forecasting without data snooping abstract data snooping arises when the properties of a data series influence the researcher s choice of model specification when data has been snooped tests undertaken using the same series are likely to be misleading this study seeks to predict equity market volatility using daily data on u k stock market returns over the period 1955 1989 we find that even apparently innocuous forms of data snooping significantly enhance reported forecast quality and that relatively sophisticated forecasting methods operated without data snooping often perform worse than naive benchmarks for predicting stock market volatility we therefore recommend two alternative models both of which are extremely simple

does vix or volume improve garch volatility forecasts abstractthis article considers whether the inclusion of two additional variables can improve volatility forecasts over a standard garch based model we consider three alternative ways of incorporating the volatility index vix and trading volume as exogenous variables within a selection of garch models we are particularly interested in whether these variables have additional incremental forecast power over and above the baseline garch specification our results suggest that both the vix and volume do provide some additional forecast power and this is generally improved when considering both of these series jointly in the model however while the results may be statistically significant the gain is marginal and the coefficient values small moreover in a horse race exercise vix does not outperform the garch approach in answering the question of whether vix produces better forecasts than the garch model then the answer is no but the informational content of vix cannot be ignored and should be incorp

unemployment insurance and short time compensation the effects on layoffs hours per worker and wages we analyze two unemployment insurance systems in one unemployed workers receive benefits while those on reduced hours do not as in north america at least until recently in the other short time compensation is paid to workers on reduced hours as in europe the first system causes inefficient temporary layoffs for some parameters the latter does not but implies inefficient hours per worker some evidence is presented regarding these effects despite policymakers recent enthusiasm for short time compensation the clear implication of this project is that changes should come on the tax not benefit side of the system

capital requirements for securities firms regulatory authorities set capital requirements to cover the position risk of securities firms and to protect against losses arising from fluctuations in the value of their holdings the requirements may be set using the comprehensive approach required by the u s securities and exchange commission the building block approach required by the european community or the portfolio approach required by the united kingdom we compare these three alternatives using a large sample of u k equity trading books the portfolio approach systematically specifies larger requirements for riskier books and vice versa it is more efficient than the building block approach and far more efficient than the comprehensive approach

a supplier s optimal quantity discount policy under asymmetric information in the supply chain literature an increasing body of work studies how suppliers can use incentive schemes such as quantity discounts to influence buyers ordering behaviour thus reducing the supplier s and the total supply chain s costs various functional forms for such incentive schemes have been proposed but a critical assumption always made is that the supplier has full information about the buyer s cost structure we derive the optimal quantity discount policy under asymmetric information and compare it to the situation where the supplier has full information

sub supply chain coordination in a three layer chain under demand uncertainty and random yield in production abstract one of the major objectives of modern supply chain management is to deal with the growing decentralization among the involved entities and hence minimizing the double marginalization effect inside the chain especially when the end customers demand is not deterministic to address this a three layer supply chain with one raw material supplier one manufacturer and one retailer is developed and studied in this paper effects of both supply chain coordination as well as sub supply chain coordination are examined optimal order and production quantities are obtained for the centralized system which depicts the scenario under coordination optimal order quantities and expected profits of the individual channel actors are maximized locally in the decentralized system under commonly used price only contract semi integrated models are also studied under price only contract the optimal strategies under different power structures are compared and the effects of the channel parameters on the optimal strategies are also examined numerical example is given to illustrate the developed model

the relationship between production and unemployment in japan okun s law in comparative perspective abstract this paper studies the question whether the celebrated okun s law a relation between excess capacity and unemployment applies to the postwar japanese economy though the fitness of estimation is weak the coefficient that measures the responsiveness of the output gap to the unemployment rate is very large reaching 28 this large coefficient can be attributed to the elastic response in the female participation ratio to flexible working hours to the slow adjustment in employment and to changes in industrial structures the results are compared with those in the united states

on sequential commitment in the price dependent newsvendor model abstract we investigate the effect of sequential commitment in the decentralized newsvendor model with price dependent demand sequential commitment allows the self profit maximizing parties to commit to contract parameters e g wholesale price retail price buyback price and order quantity sequentially and alternately and we investigate its effect on the equilibrium profits of the channel and its members sequential commitment introduces more flexibility to contracting in the supply chain and our analysis can provide some insight to channel members who follow a bargaining process to determine the values of contract parameters we show that the introduction of sequential commitment to the price dependent pd newsvendor model with buybacks can significantly improve the manufacturer s and the channel expected profits but it can also decrease the retailer s expected profit finally we demonstrate that with sequential commitment under some conditions the choice of the first mover is endogenized and we identify the unique sequence of commitments by channel members that would arise in equilibrium

multiple lot sizing and value of probabilistic information in production to order of an uncertain size abstract a make to order batch manufacturer knows that an order for items with some particular specifications is forthcoming but does not yet know the exact size of the order due to production lead times work needs to start immediately but some units produced may fail to meet required tolerances that is the yield of each batch is random each new run involves a costly setup and each unit attempted involves material and other variable costs if a subjective probability distribution for the order size can be formed the following related questions arise 1 a what is the optimal run size 2 b when should production stop to answer these questions this paper formulates a new model whose main new feature is the ability to handle uncertain demand within a multiple lot sizing setting it is proved that the optimal policy for this scenario is one of control limit stop if and only if the stock of good units is larger than some critical value a computer program was developed for solving the problem for binomial yields and optimal policies for several examples are reported due to the effort required to form and communicate probabilistic forecasts a common practice is to express a forecast as a single number corresponding perhaps to the mean or median of the unarticulated distribution we compute the extra profit expected from forming and using probabilistic forecasts we also show how to compute the profit s variance for any policy

the persistence of volatility and stock market fluctuations this paper examines the potential influence of changing volatility in stock market prices on the level of stock market prices it demonstrates that volatility is only weakly serially correlated implying that shocks to volatility do not persist these shocks can therefore have only a small impact on stockmarket prices since changes in volatility affect expected required rates of return for relatively short intervals these findings lead us to be skeptical of recent claims that the stock market s poor performance during the 1970 s can be explained by volatility induced increases in risk premia this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item

the impacts of the full returns policy on a supply chain with information asymmetry abstract in contrast to the existing return policies literature assuming that information is symmetrical between the manufacturer and the retailer we study the full returns policy s impact on supply chains with information asymmetry we first study the case that the base level of the demand follows a discrete distribution with two states we find that the retailer benefits from the full returns policy in all circumstances while the manufacturer and the supply chain are better off under some conditions we then consider the situation in which the base level of the demand is a type of ar 1 process

note the role of returns policies in pricing and inventory decisions for catalogue goods manufacturers often use returns policies to encourage retailers to stock and price items more aggressively we focus on the effect that such policies have on both a retailer s and a manufacturer s profits when the retailer must commit prior to the selling season to both a stocking quantity and a price at which to sell an item such a commitment is often necessary for retailers who sell primarily through catalogues

implicit contracts a survey 7mplicit contracts resolve the distribution of uncertainty and utilization of specific human capital between risk averse workers and less risk averse firms incomplete contracts are required to yield involuntary layoffs in contract markets otherwise contracts are efficient and pareto optimal by construction there is a close relation between contract theory and neoclassical labor market theory contracts smooth consumption but increase the volatility of labor supply and labor utilization to demand disturbances because contractural insurance eliminates the income effects of socially diversifiable risks this result is similar to the intertemporal substitution hypothesis however the price mechanism in a contract is substantially different contracts embody a nonlinear two part pricing scheme the lump sum part allocates the income consumption consequences of risks and the marginal pricing part allocates production and labor utilization this implicit pricing mechanism is in all respects flexible though the observed average hourly wage combines both parts and may give the outward appearanceof rigidity furthermore the observed average wage rate in a contract does not reflect marginal conditions necessary for structural econometric estimation indivisibilities appear necessary to account for the split between work sharing and layoffs contracts with private information are also considered in the nonlinear pricing context this abstract was borrowed from another version of this item

the quantity flexibility contract and supplier customer incentives consider a supply chain consisting of two independent agents a supplier e g a manufacturer and its customer e g a retailer the latter in turn serving an uncertain market demand to reconcile manufacturing procurement time lags with a need for timely response to the market such supply chains often must commit resources to production quantities based on forecasted rather than realized demand the customer typically provides a planning forecast of its intended purchase which does not entail commitment benefiting from overproduction while not bearing the immediate costs the customer has incentive to initially overforecast before eventually purchasing a lesser quantity the supplier must in turn anticipate such behavior in its production quantity decision this individually rational behavior results in an inefficient supply chain this paper models the incentives of the two parties identifying causes of inefficiency and suggesting remedies particular attention is given to the quantity flexibility qf contract which couples the customer s commitment to purchase no less than a certain percentage below the forecast with the supplier s guarantee to deliver up to a certain percentage above under certain conditions this method can allocate the costs of market demand uncertainty so as to lead the individually motivated supplier and customer to the systemwide optimal outcome we characterize the implications of qf contracts for the behavior and performance of both parties and the supply chain as a whole

forecasting volatility and volume in the tokyo stock market long memory fractality and regime switching abstract we investigate the predictability of both volatility and volume for a large sample of japanese stocks the particular emphasis of this paper is on assessing the performance of long memory time series models in comparison to their short memory counterparts since long memory models should have a particular advantage over long forecasting horizons we consider predictions of up to 100 days ahead in most respects the long memory models arfima figarch and the recently introduced multifractal model dominate over garch and arma models however while figarch and arfima also have quite a number of cases with dramatic failures of their forecasts the multifractal model does not suffer from this shortcoming and its performance practically always improves upon the naive forecast provided by historical volatility as a somewhat surprising result we also find that for figarch and arfima models pooled estimates i e averages of parameter estimates from a sample of time series give much better results than individually estimated models

optimal soft order revisions under demand and supply uncertainty and upstream information abstract demand patterns for products with short life cycles or seasonal demand do not follow a discernible pattern for individual sales events and seasons due to uncertainty associated with effectiveness of product promotions willingness of major retailers to carry product and their support competition and other unforeseen marketplace events factors these atypical demand patterns can be volatile and unsuitable for traditional demand forecasting in such cases buyers utilize market signals to regularly update demand forecasts under these settings sharing early soft order i e order forecast with the supplier reduces buyer s risk of supply shortages in this study we propose an optimal order revision policy for a buyer facing atypical demand and supply uncertainty for a single selling season based on a stochastic dynamic program we demonstrate the value of soft orders as well as supplier s inventory position information for the buyer we make several key contributions i we introduce a decision model for buyer to optimally revise soft orders under supply uncertainty with or without supplier s inventory position information under a deposit scheme ii we characterize the relationship between the optimal soft order and final firm order under demand forecasts and revisions demonstrating that optimal orders may be aggressive conservative or match the demand forecast iii we identify settings under which inventory position information of the supplier is beneficial to the buyer iv we offer a mechanism for identifying the minimum unit deposit cost that will lead to truthful soft orders from the buyer a detailed analysis explores the structure of the optimal ordering policies as well as the effect of cost parameters and sources of uncertainty on buyer performance

standard deviations implied in option prices as predictors of future stock price variability abstract standard deviations implied in option prices have recently been introduced as being better than average predictors of future stock price variability this article specifically studies the predictive ability of implicit standard deviations taking into account the dividend problem and the problem of optimal weighting schemes of the standard deviations when there are several options on the same stock transaction data information was used to study the importance of non simultaneities in observing stock and option prices

coordination of supply chains with a flexible ordering policy under yield and demand uncertainty this paper studies a flexible ordering policy among a manufacturer and a supplier with random yield and demand uncertainty where the order quantity lies between the minimum and the maximum quantity we first determine the optimal flexible ordering policy and the corresponding raw material production quantity that maximize expected profit of the centralized supply chain and find that our flexible ordering policy can significantly enhance the supply chain s expected profit compared to an invariable ordering policy then we analyze the decentralized scenario and propose a revenue sharing policy with an order penalty and rebate opr contract to fully coordinate the supply chain finally numerical examples are given to illustrate the results