a semiparametric approach to short term oil price forecasting abstract in this paper it is shown how the garch properties of oil price changes can be employed to forecast the oil price distribution over short term horizons the forecasting methodology is semiparametric and it is based on the bootstrap approach the results of an out of sample forecasting exercise carried out using the brent oil price series suggest that the forecasting approach can be used to obtain a performance measure for the forward price in addition to compute interval forecasts for the oil price

an empirical exploration of the world oil price under the target zone model abstract this paper investigates the behavior of the world oil price based on the first generation target zone model using anecdotal data during the period of 1988 1999 we found that opec has tried to maintain a weak target zone regime for the oil price our econometric tests suggest that the movement of the oil price is not only manipulated by actual and substantial interventions by opec but also tempered by market participants expectations of interventions as a consequence the non linear model based on the target zone theory has very good forecasting ability when the oil price approaches the upper or lower limit of the band

involuntary unemployment and implicit contracts this paper provides an explanation of involuntary umemployment arising as a consequence of asymmetric information between firms and workers involuntary unemployment is defined as a situation where ex post gains to trade exist a model of labor contracts is developed where the allocations are not ex post optimal it is shown that inferiority of leisure is a necessary and sufficient condition for the existence of involuntary unemployment

reducing the mean supply delay of spare parts using lateral transshipments policies lateral transshipment has been studied lately as a promising policy for increasing the performances of multi echelon spare parts inventory system by lateral transshipment spare parts can be moved from one location with excess inventory to another location at the same echelon in shortage with the aim of reducing supply delays of spare parts this paper will examine the relative effectiveness of two lateral shipments approaches in reducing the mean supply delay msd of a non repairable item with respect to a classical policy of no lateral shipments a simulation model of a two echelon supply network has been implemented and an experiment has been performed by varying different parameters of the supply network such as the number of warehouses locations at the lower echelon the supply lead time from the central depot the spare parts demand uncertainty and the size variability of the warehouses results show appreciable reductions of msd when lateral shipments are allowed with respect to the classical policy in almost every network configuration

wage employment contracts this paper studies the efficient agreements about the dependence of workers earnings on employment when the employment level is controlled by firms the firms superior information about profitability conditions is responsible for this form of contract governance under plausible assumptions such agreements will cause employment to diverge from efficiency as a byproduct of their attempt to mitigate risk it is shown that if leisure is a normal good and firms are risk neutral employment is always above the efficient level such a one period implicit contracting model cannot therefore be used to explain unemployment as a rational byproduct of risk sharing between workers and a risk neutral firm under conditions of asymmetric information

generating real persistent effects of monetary shocks how much nominal rigidity do we really need abstract this paper attempts to assess whether money can generate persistent economic fluctuations in dynamic general equilibrium models of the business cycle we show that a small nominal friction in the goods market can make the response of output to monetary shocks large and persistent if it is amplified by real wage rigidity in the labor market we also argue that for plausible levels of real wage rigidity a small degree of nominal stickiness is sufficient for money to produce economic fluctuations as persistent as those observed in the data

implicit contracts and the cyclicality of the skill premium to examine the cyclical behavior of the skill premium this paper introduces implicit labor contracts in a dsge model where production is characterized by capital skill complementarity and the utilization of capital is endogenous it is shown that this model can reproduce the observed cyclical patterns of wages and the skill premium the feature of capital skill complementarity coupled with variable capital utilization rates does not come at odds with the acyclical behavior of the skill premium the paper argues that the skill complementarity of capital is not a quantitatively significant factor at high frequencies the key aspects are the contracts and the capital utilization margin

enhanced lateral transshipments in a multi location inventory system in managing an inventory network two approaches to the pooling of stock have been proposed reactive transshipments respond to shortages at a location by moving inventory from elsewhere within the network while proactive stock redistribution seeks to minimize the chance of future stockouts this paper is the first to propose an enhanced reactive approach in which individual transshipments are viewed as an opportunity for proactive stock redistribution we adopt a quasi myopic approach to the development of a strongly performing enhanced reactive transshipment policy in comparison to a purely reactive approach to transshipment service levels are improved while a reduction in safety stock levels is achieved the aggregate costs incurred in managing the system are significantly reduced especially so for large networks moreover an optimal policy is determined for small networks and it is shown that the enhanced reactive policy substantially closes the gap to optimality

a new decision rule for lateral transshipments in inventory systems this paper deals with a single echelon inventory system consisting of a number of parallel local warehouses facing compound poisson demand there are standard holding and backorder costs as well as ordering costs at all warehouses normally the warehouses replenish from an outside supplier however lateral transshipments between the warehouses are also possible such transshipments take no time but incur additional costs when a demand occurs at a warehouse the question is whether the whole demand or part of it should be covered by a lateral transshipment from another warehouse given a set of alternative decisions our decision rule minimizes the expected costs under the assumption that no further transshipments will take place this rule is then used repeatedly as a heuristic a simulation study illustrates how the suggested technique performs under different conditions

self enforcing employment contracts and business cycle fluctuations abstract this paper incorporates risk sharing employment contracts into an economy in which matching frictions characterize the labour market and in which agents cannot commit in equilibrium the terms of ongoing contracts are affected by those being negotiated in the job market because contracts must be self enforcing in this context risk sharing implies that hours worked and wages are negatively related while enforcement considerations imply the converse overall the sign of this relationship is ambiguous therefore the existence of such contracts may explain why movements in hours worked appear weakly related to those in real wages in u s aggregate data

a semi markov decision problem for proactive and reactive transshipments between multiple warehouses abstract lateral transshipments are an effective strategy to pool inventories we present a semi markov decision problem formulation for proactive and reactive transshipments in a multi location continuous review distribution inventory system with poisson demand and one for one replenishment policy for a two location model we state the monotonicity of an optimal policy in a numerical study we compare the benefits of proactive and different reactive transshipment rules the benefits of proactive transshipments are the largest for networks with intermediate opportunities of demand pooling and the difference between alternative reactive transshipment rules is negligible

labor contracts and business cycles this paper investigates the claim often put forth by real business cycle proponents that the poor performance of their models in matching real world aggregate labor market behavior is due to the fact that observed real wage payments do not correspond to the actual marginal productivity of labor but contain an insurance component that cannot be accounted for by the walrasian pricing mechanism to test this idea we dispense with the walrasian description of the labor market and introduce contractual arrangements between employees and employers assuming that employees are prevented from accessing capital markets and are more risk averse than employers we use the theory of optimal contracts to derive an equilibrium relation between aggregate states of the economy and wage labor outcomes this contractual arrangement is then embedded into a standard one sector stochastic neoclassical growth model in order to look at the business cycle implications of the contractual hypothesis the resulting dynamic equi

target zones and exchange rate dynamics this paper develops a simple model of exchange rate behavior under a target zone regime it shows that the expectation that monetary policy will be adjusted to limit exchange rate variation affects exchange rate behavior even when the exchange rate lies inside the zone and is thus not being defended actively somewhat surprisingly the analysis of target zones turns out to have a strong formal similarity to problems in option pricing and investment under uncertainty

wages business cycles and comparative advantage abstract the standard equilibrium models of business cycles face a puzzling fact that total hours vary greatly over the business cycle without much variation in aggregate wages the model augments the standard rbc model to include lucas span of control distinction between market and non market and managerial and non managerial work makes aggregate wages far less cyclical than individual wages cross sectional comparative advantage between market and non market sector in the workforce substantially increases the response of aggregate hours to shifts in relative productivity as a result the model provides a reconciliation between data and equilibrium macroeconomics

target zones and exchange rates an empirical investigation this paper develops an empirical model of exchange rates in a target zone the distribution of exchange rate changes is conditioned on a latent jump variable where the probability and size of a jump vary over time as a function of financial and macroeconomic variables when there is no jump the target zone is credible and exchange rate changes are constrained to remain within the target zone band the paper revisits the empirical evidence from the european monetary system regarding the conditional distribution of exchange rate changes the credibility of the system and the size of the foreign exchange risk premia in contrast to some previous findings we conclude that the french franc deutschmark rate exhibits considerable nonlinearities realignments are somewhat predictable and the credibility of the system did not increase substantially after 1987 moreover our model implies that the foreign exchange risk premium becomes large during speculative crises

physical market determinants of the price of crude oil and the market premium abstract we analyze the determinants of the real price of crude oil by means of an equilibrium correction model over the last two decades where we focus on the aspects of the physical market that impact on the clearing price we find that two cointegrating relations affect the changes in prices one refers to opec s behavior attempting to control prices using its market power and quotas the other to the coverage rate of oecd expected future demand using inventory behaviors we derive a forecasting equation for the change in oil prices which we use to assess the speculative elements of the price increases of the period 2000 05 we show that worries alien to the physical markets were the causes of the increase in oil prices and we quantify their overall impact

wage rigidity and job creation recent research in macroeconomics emphasizes the role of wage rigidity in accounting for the volatility of unemployment fluctuations we use worker level data from the cps to measure the sensitivity of wages of newly hired workers to changes in aggregate labor market conditions the wage of new hires unlike the aggregate wage is volatile and responds almost one to one to changes in labor productivity we conclude that there is little evidence for wage rigidity in the data

redistributive shocks and productivity shocks abstract a productivity innovation reduces labor share at impact making it countercyclical it subsequently produces a long lasting increase that peaks five years later at a level larger in absolute terms than the initial drop before slowly returning to average i e labor share overshoots we estimate a bivariate shock process to the production function that under competition in factor markets accounts for this overshooting we pose this process in an otherwise standard real business cycle economy and we find that the contribution of productivity innovations to the variance of hours is 1 of that in the standard rbc model

the extreme value in crude oil and us dollar markets abstract this study constructs a flexible range based volatility model by considering extreme value information to explore the volatility and dependence structures between the oil price and the us dollar exchange rate an asset allocation strategy is implemented to evaluate the economic value and confirm the efficiency of this model the empirical results indicate that the use of extreme value information can not only enhance the explanatory power of volatility structures but also sort out the asymmetric volatility effect in the oil market besides investors can obtain extra benefits of between 72 and 713 annualized basis points by incorporating extreme value information into their asset allocation strategies less risk averse investors can generate higher benefits the empirical results have potentially important implications for asset allocation and risk management

approximate dynamic programming for lateral transshipment problems in multi location inventory systems abstract companies commonly allocate their inventories across multiple locations based on their historical sales rates however random fluctuations in customer purchases such as those caused by weather conditions and other external factors might cause significant deviations from expected demand leading to excess stock in some locations and stockouts in others to fix this mismatch companies often turn to lateral transshipments e g the movement of stock between locations of the same echelon in this paper we examine multi location inventory systems under periodic review with multiple opportunities for proactive transshipments within one order cycle if stockouts occur demand is lost with no opportunity to backorder the objective of our model is to find an optimal policy that indicates the sources and the destinations of transshipments as well as the number of units to maximise the profit of the network we create a dynamic program that can in principal be solved to optimality using bellman s equation however the size of the state and decision spaces makes it impossible to find the optimal policy for real world sized problem instances thereby we use forward approximate dynamic programming to find a near optimal transshipment policy finally we conduct an extensive numerical study to gauge the performance of our transshipment policy for small size instances we compare our policy to the optimal one for larger scale instances we consider other practically oriented heuristics our numerical experiments show that our proposed algorithm performs very well compared to state of the art methods in the literature

optimal r q inventory policies with poisson demands and lost sales discounted and undiscounted cases abstract we consider a continuous review r q inventory system with poisson demands and at most one order outstanding the replenishment lead time is either constant or exponentially distributed demands not covered immediately from inventory are lost costs include a linear order cost with a fixed cost per order and a fixed cost per unit lost sale as regards inventory holding costs the cost of capital often constitutes a major part this paper focuses on these interest related holding costs in the undiscounted case holding costs are linear and inventory performance is measured by the long run average total cost incurred per unit time in the discounted case the performance measure is the expected present value of the ordering and lost sales costs the cost associated with capital tied up in inventory is accounted for by an appropriate discount rate we formulate an exact model and design a policy iteration algorithm for the discounted case results on the form of an optimal replenishment policy are derived and the model is compared to a previously derived model for the undiscounted case numerical experiments are used to evaluate the difference between the optimal solutions with and without discounting the effect of a stochastic lead time on this difference is also considered by comparing solutions with constant and exponential lead times in general the differences seem to be fairly small but exceptional cases exist when the service level is low

ces technology and business cycle fluctuations we contribute to an emerging literature that brings the constant elasticity of substitution ces specification of the production function into the analysis of business cycle fluctuations using us data we estimate by bayesian maximum likelihood methods a standard medium sized dsge model with a ces rather than cobb douglas cd technology we estimate a elasticity of substitution between capital and labour well below unity at 0 15 0 18 in a marginal likelihood race ces decisively beats the cd production and this is matched by its ability to fit the data better in terms of second moments we show that this result is mainly driven by the implied fluctuations of factor shares under the ces specification the ces model performance is further improved when the estimation is carried out under an imperfect information assumption hence the main message for dsge models is that we should dismiss once and for all the use of cd for business cycle analysis

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

near optimal r q policies for a two stage serial inventory system with poisson demand we consider a two stage serial inventory system whose cost structure exhibits economies of scale in both stages in the system stage 1 faces poisson demand and replenishes its inventory from stage 2 and the latter stage in turn orders from an outside supplier with unlimited stock each shipment either to stage 2 or to stage 1 incurs a fixed setup cost we derive important properties for a given echelon stock r q policy for an approximation of the problem where all states are continuous based on these properties we design a simple heuristic algorithm that can be used to find a near optimal r q policy for the original problem numerical examples are given to demonstrate the effectiveness of the algorithm

capital labor substitution and equilibrium indeterminacy empirical evidence indicates that the elasticity of capital labor substitution for the aggregate u s economy is below unity in contrast the existing indeterminacy literature has mostly restricted attention to a cobb douglas production function which imposes a substitution elasticity exactly equal to unity this paper examines the quantitative relationship between capital labor substitution and the conditions needed for equilibrium indeterminacy and belief driven fluctuations in a one sector growth model with variable capital utilization the substitution elasticity has little quantitative impact on the minimum degree of increasing returns needed for indeterminacy however when capital utilization is constant a below unity substitution elasticity sharply raises the minimum degree of increasing returns in this version of the model lower substitution elasticities impose a higher adjustment cost on labor hours that cannot be mitigated by shifts in the capital utilization rate overall our results show that empirically plausible departures from the cobb douglas specification can make indeterminacy more difficult to achieve

the consequences of rigid wages in search models the standard theory of equilibrium unemployment the mortensen pissarides search and matching model cannot explain the magnitude of the business cycle fluctuations in two of its central elements unemployment and vacancies modifying the model to make the present value of wages unresponsive to current labor market conditions amplifies fluctuations in unemployment and vacancies by an order of magnitude significantly improving the performance of the model despite this the welfare consequences of such rigid wages is negligible jel e24 e32 j30 j41 j63 j64

anticipated and unanticipated effects of crude oil prices and gasoline inventory changes on gasoline prices abstract this paper examines the effect of anticipated and unanticipated changes in oil prices and gasoline inventory on us gasoline prices we estimate empirical responses to anticipated and unanticipated changes in oil prices and gasoline inventory and show that gasoline price adjustments are faster and stronger for anticipated changes in oil prices and inventory levels than for unanticipated changes furthermore this difference is statistically significant we use these findings to evaluate the cost of adjustment hypothesis suggested by borenstein and shephard 2002 we also find that there is an asymmetry in the effect of gasoline inventory on gasoline and oil prices this finding complements a well known result that positive and negative changes in oil prices have asymmetric effect on gasoline prices

excess sensitivity of consumption to current income liquidity constraints or myopia this paper asks whether the empirical rejection of the rational expectations permanent income hypothesis occurs because agents are myopic in the sense that the marginal propensity to consume out of transitory income is non zero or because some agents face liquidity constraints the finding that the estimate of the mpc out of transitory income is dramatically affected in both magnitude and statistical significance by the inclusion of a proxy for liquidity constraints suggests that liquidity constraints are an important part of the explanation of the observed excess sensitivity of consumption to current income la sensibilite excessive de la consommation au revenu courant contraintes sur la liquidite ou myopie ce memoire examine la question a savoir pourquoi l hypothese du revenu permanent avec anticipations rationnelles n est pas v6rifiee empiriquement est ce parce que les agents economiques sont myopes i e que leur propension marginale a consommer a partir de leur revenu transitoire n est pas nulle ou bien est ce que certains agents economiques font face a des contraintes sur leur liquidite le fait que l estimation de la propension marginale a consommer le revenue transitoire est affectee par l inclusion d une variable qui tente de capturer l importance des contraintes sur la liquidit6 tant dans l 6valuation de sa taille que dans sa signification statistique suggere que ces contraintes jouent un role important dans l explication de cette sensibilite excessive qu on observe de la consommation aux changements dans le niveau de revenu courant almost all the recent empirical tests of the rational expectations permanent income hypothesis re pih have rejected the hypothesis using a rich variety of data sets and estimation methods the empirical work indicates that the failure of the re pih is significant both statistically and quantitatively the null hypothesis in this empirical literature typically consists of the joint hypothesis that 1 agents expectations are formed rationally 2 desired consumption is determined by permanent income and 3 capital markets are perfect in the sense that agents can lend or borrow against 1 studies rejecting the re pih include blinder 1981 flavin 1981 hall and mishkin 1982 hayashi 1982 and sargent 1978 in his original paper hall 1978 did not reject the re pih decisively however flavin 1981 showed that with a minor alteration in the specification of the alternative hypothesis the re pih could be rejected using hall s test and data set bernanke 1981 studying panel data on automobile expenditures did not find evidence against the hypothesis for an extensive survey of the empirical literature on the rational expectations permanent income hypothesis see king 1983 canadian journal of economics revue canadienne d economique xviii no 1 february fevrier 1985 printed in canada imprime au canada 0008 4085 85 117 36 1 50 canadian economics association this content downloaded from 157 55 39 17 on wed 31 aug 2016 05 08 58 utc all use subject to http about jstor org terms

an interpretation of recent research on exchange rate target zones how do exchange rate bands work compared to completely fixed rates between realignments or more precisely what are the dynamics of exchange rates interest rates and central bank interventions within exchange rate bands does the difference between bands and completely fixed exchange rates matter and if so which of the two arrangements is best or more precisely what are the tradeoffs that determine the optimal bandwidth this article will present an interpretation of some selected recent theoretical and empirical research on exchange rate target zones with emphasis on main ideas and results and without technical detail

who benefits from transshipment exogenous vs endogenous wholesale prices this paper studies how transshipments affect manufacturers and retailers considering both exogenous and endogenous wholesale prices for a distribution system where a single manufacturer sells to multiple identical cost retailers we consider both the manufacturer being a price taker and the manufacturer being a price setter in a single period setup under multivariate normal demand distribution in the case of the manufacturer being a price taker we provide several analytical results regarding the effects of key parameters on order quantities and profits in the case of the manufacturer being a price setter we characterize the stackelberg game that arises and provide several insights into how the game dynamics are affected by transshipments specifically we find that risk pooling makes retailers order quantities less sensitive to the wholesale price set by the manufacturer hence in general the manufacturer benefits from retailers transshipments by charging a higher wholesale price while retailers are often worse off the paper captures the effect of demand correlation and the effect of the number of retailers throughout and it illustrates the findings by a numerical example we also provide an interactive web page for numerical experiments

the observational implications of labor contracts in a dynamic general equilibrium model economies are studied where labor contracts even without changing real allocations can make equilibria appear different one basic example is that wage observations generated by long term employment contracts are biased measures of theoretical market wages this idea is analyzed in a dynamic stochastic economic model including both overlapping generations of finite lived workers and infinite horizon employers so that the implications for business cycle life cycle and cross sectional phenomena can be explicitly addressed understanding contracts in this way potentially allows us to reconcile several ostensibly anomalous aspects of the data with equilibrium theory

indivisible labor lotteries and equilibrium abstract this paper considers an economy where labor is indivisible and agents are identical although the discontinuity in labor supply at the individual level disappears as a result of aggregation it is shown that indivisible labor has strong consequences for the aggregate bahavior of the economy it is also shown that optimal allocations involve lotteries over employment and consumption

combined demand and capacity sharing with best matching decisions in enterprise collaboration abstract demand and capacity sharing dcs among entities within a supply network are common practice and have become attractive strategies for competing and non competing supply enterprises ses examples include airlines test and assembly factories and outsourced maintenance and logistics providers the purpose maximize profit and resource utilization enable timely delivery to customers in spite of uncertain market demands and unexpected capacity shortages and maximize the overall stability dcs protocols are defined for the ses with capacity shortage known as demand sharing ses to utilize excess capacities of other ses known as capacity sharing ses thus fulfilling their current customers demand more effectively while eliminating excess inventory of capacity sharing ses these dcs roles vary over time high frequency of dcs decisions could impose additional costs to the collaborative network of ses cnse in terms of transactions negotiations and lateral transshipment of stocks between ses attention must be paid to the inevitable costs of collaboration for dcs best matching bm protocol is proposed to minimize the dcs costs through dynamic matching of ses and customers with respect to the customers demand and ses available capacity to share bm protocol is also applied for finding the best matches between dcs proposals during collaboration negotiations among ses a novel mixed integer programming mip formulation is developed for modeling and analyzing the combined dcs bm decisions the dcs bm model is then validated using the queuing theory it is shown mathematically and through numerical experiments that the dcs bm model 1 outperforms the previous non collaborative models in terms of resource utilization and stability and 2 provides a dominating strategy compared with both collaborative and non collaborative models for optimizing the total cnse profit and service level

why do oil prices jump or fall this paper discusses theories that can explain the zig zags of oil prices in general and in particular the recent jump more precisely the following explanations are discussed homo oeconomicus pure profit maximization if demand is dynamic and convex price reaction function price increases and respectively declines depend on capacity utilization cartelization contingent on output or revenues of which the latter can lead to backward bending supply segments and multiple equilibria statistical descriptions mean reversion homo politicus i e arguments for price hikes that are rational public choice despite the long run economic loss finally two approaches are presented that emphasize demand uncertainty one extending the above mentioned dynamic demand framework and the other considers a dynamic game of non competitive suppliers with lumpy investments summing up a demand shock seems to be the most suitable explanation of today s high prices indeed a shock given that international energy agency iea and department of energy doe were promising just a couple of years ago that we are going to have lots of oil at low prices while others and in particular politics have surprisingly little or no explanatory power

dynamic balancing of inventory in supply chains abstract we consider the dynamic version of the classic problem of allocation of inventories to a set of retailers to rectify the imbalance of inventories amongst them while most research is focussed on analyzing different allocation strategies with a predetermined time of shipment static policy we investigate the benefit of using real time demand inventory information to schedule rebalancing shipments in a retail network we model the dynamic rebalancing problem that has two decisions the timing of the balancing shipments and determination of the new stocking levels at the retailers as a dynamic program dp we obtain structural properties for the optimal allocation rebalancing and timing strategies we also present conditions under which a greedy heuristic to decide how much to ship from one retailer to another is optimal the dp for determining the optimal timing and quantity of shipments has a very large state space we present an algorithm to solve this dp efficiently we also provide a heuristic solution procedure to the dynamic problem that performs very close to optimal numerical results show that dynamic allocation policies can lead to substantial benefits over the static policy especially in systems in which the starting inventories at the retailers are balanced or when high service levels are required

who is credit constrained in the u s economy an important assumption of the life cycle model of consumption is the postulate of perfect capital markets this hypothesis has recently been challenged by substantial empirical evidence hall and mishkin 1982 using the panel study of income dynamics estimate that 20 percent of united states families are liquidity constrained mariger 1986 derives a life cycle model with endogenous liquidity constraints and using a cross section estimates this fraction to be 19 4 percent hubbard and judd 1986 simulate a model with a constraint on net worth which shows that with reasonable assumptions about preferences 19 0 percent of united states consumers are liquidity constrained the emerging consensus points therefore to a fraction of approximately 20 percent of the population behaving in a manner that is inconsistent with the pure life cycle model in addition hayashi 1985 and zeldes 1989 investigate the correlation among consumption wealth and income for various population groups and infer that liquidity constraints are more important for younger families with low levels of wealth and saving the main limitation of these studies is that in their data sets constrained consumers are not observable and have to be identified via indirect evidence thus there is as yet little firm evidence about the characteristics of the consumers who are likely to be credit constrained this paper adopts an approach that differs from previous tests for liquidity constraints because it makes use of data where constrained consumers are observable and explicitly links their existence to credit market imperfections and personal characteristics the data drawn from the 1983 survey of consumer finances scf and described in section ii provide information on individuals whose request for credit has been rejected by financial intermediaries in section iii a model is developed in which consumers and lenders behavior jointly determines the probability that a consumer is rationed in the credit market this probability is then

market entry and international propagation of business cycles abstract in this paper pro cyclical market entry acts as an international transmission mechanism for business cycle shocks in an imperfectly competitive dynamic equilibrium model an expansion in one open economy leads to additional business formation in a parallel large open economy through demand spillovers business formation causes a decline in markups leading to an expansion in employment production and investment in both economies the modeling of the entry decision is critical only when the entry game is modelled as sequential with incumbents enjoying a first mover advantage are markups sufficiently elastic to cause international comovement

endogenous business cycle propagation and the persistence problem the role of labor market frictions contrasting sharply with a recent trend in dsge modeling we propose a business cycle model where frictions and shocks are chosen with parsimony the model emphasizes a few labor market frictions and shocks to monetary policy and technology the model estimated from u s quarterly postwar data accounts well for important differences in the serial correlation of the growth rates of aggregate quantities the size of aggregate fluctuations and key comovements including the correlation between hours and labor productivity despite its simplicity the model offers an answer to the persistence problem chari et al 2000 that does not rely on multiple frictions and adjustment lags or ad hoc backward looking components we conclude modern dsge models need not embed large batteries of frictions and shocks to account for the salient features of postwar business cycles

a geopolitical theory of oil price behaviour an econometric evaluation previous work on crude oil price modelling has generally focused on two theoretical approaches either the optimal control analysis of pricing of a depletable resource or organization of the petroleum exporting countries opec as a partial monopolist setting oil prices to maximize net present value neither has been wholly satisfactory we consider a different perspective a cooperative framework in which political and military factors interacted with economic considerations for oil exporters and importers to define a target price zone tpz we analyse several issues in this context monthly versus annual average prices beginning and ending dates for tpzs degree of stability in several price series west texas intermediate wti brent etc free on board fob and landed prices real or nominal prices opec behaviour and effect of the euro exchange rate on dollar denominated oil prices we conclude that a tpz system was in operation from 1986 through 2003 the tpz worked imperfectly but with a sub

the effect of liquidity constraints on consumption a cross sectional analysis this paper examines the effect of liquidity constraints on consumption expenditures using a single year cross section data set a reduced form equation for consumption is estimated on high saving households by the tobit procedure to account for the selectivity bias since high saving households are not likely to be liquidity constrained the estimated equation is an appropriate description of how desired consumption that would be forthcoming without liquidity constraints is related to the variables available in the cross section data when the reduced form equation is used to predict desired consumption the gap between desired consumption and measured consumption is most evident for young households

estimating and forecasting the real prices of crude oil a data rich model using a dynamic model averaging dma approach given that oil price fluctuations have been of great interest for macroeconomics in the recent years due to its important implications for future inflation economic growth and policy making the aim of this paper is to estimate and forecast west texas intermediate wti crude oil prices using a large monthly dataset that covers the period from march 1983 to december 2011 to achieve this aim forecasting with factor models offers a usual approach that utilizes large datasets however a forecasting model which simply includes all factors in state space equation and does not allow for time varying may be not suitable with a highly volatile market such as oil market to overcome these limitations an approach that accounts both for parameter and model uncertainty is employed in particular this study uses the dynamic model averaging dma approach suggested by koop and korobilis 2012 the key element of the dma approach is that it allows both for model and parameter to vary at each point of time by doing so the dma is robust to structural breaks empirical findings show that dma approach outperforms any other alternative model used in the forecasting exercise results also show that there is model but not parameter variation in this oil price forecasting exercise finally the findings suggest that the dma approach provides a better proxy of expected spot prices than future prices

oil price mean reversion and zone readjustments observing opec s short term price output ceiling behavior during the late 1980s and 1990s one can conclude that it attempts to stabilize the market price within a range of its announced target price by controlling the output ceiling if the price moves within four to five dollars below the target price it usually reduces the output ceiling and assigns new quotas to its member countries to keep the price close to the target price in reality opec established a band for the market price positioned round the target price by basically choosing suitable upper and lower limits for the output or at least in soft markets it places tolerance zone below the target price in order to restrict the discrepancy between the market price and the target price the lower limit is particularly needed because it sets a price floor and ensures that the market price stays above the significantly lower marginal cost of oil production if the limits of these zones are backed by a perfectly credible intervention policy they can generate an expectations process that should turn the market prices around even before any intervention takes place while opec in some sense observes the target zones for its prices thosemore zones are neither well defined nor vigorously defended it can not always or may not be willing to maintain the price within the limits of the desired zone by cutting the output ceiling it must sometimes readjust the target price and output ceiling and thus create a new target zone to reflect the market s new fundamentals this is particularly true now because opec is losing market share to the other oil producers and is contemplating to shift the current band actual readjustments in the target price can be so large as in 1980 and 1985 that the newmarket price must jump as well they can occur when both the market price is near the limits of the band as well as when it is inside the band but still further away from those limits less

clustering in crude oil prices and the target pricing zone hypothesis abstract this paper studies the target pricing zone tpz hypothesis for crude oil by examining price clustering in the dollar digit it is hypothesized that price clustering occurs within an established tpz if opec is able to defend the upper and lower bounds through output changes the results show that prices strongly cluster around the dollar digit value of 9 within the tpz sub periods but not outside the sub periods furthermore the degree of clustering declines when production capacity utilization is high and when production significantly exceeds quotas consistent with opec s inability to defend the zone nine centered clustering also results in lower contemporaneous and next day volatility these results support the target pricing zone hypothesis of crude oil

the incentive to cheat an empirical analysis of opec relatively little is known about the payoffs to various kinds of strategies facing opec cartel members we propose an empirically tractable procedure to calculate the payoffs to relevant opec strategies fresh insights into the problem of the quota system and deterring cheating are presented stressing the importance of the nonrenewability of the oil stock the short run rigidity of demand short term capacity constraints the presence of a backstop technology and the different discount rates the cartel members are facing we conclude that punishment is a dominant strategy for the saudis and that the finite resource base in the oil industry substantially attenuates the incentive to cheat also the biased market quota system in favor of small producers weakens but does not eliminate their incentive to cheat in addition we compute the price paths and payoffs corresponding to competitive cournot and joint profit maximization solutions and contrast them with the actual historical patterns of opec beha

labor hoarding and the business cycle this paper investigates the sensitivity of solow residual based measures of technology shocks to labor hoarding behavior using a structural model of labor hoarding and the identifying restriction that innovations to technology shocks are orthogonal to innovations in government consumption we estimate the fraction of the variability of the solow residual that is due to technology shocks our results support the view that a significant proportion of movements in the solow residual are artifacts of labor hoarding behavior specifically we estimate that the variance of innovations to technology is roughly 50 percent less than that implied by standard real business cycle models in addition our results suggest that existing real business cycle studies substantially overstate the extent to which technology shocks account for the variability of postwar aggregate u s output

the dynamic stability of opec s oil price mechanism abstract this paper examines opec s long lived mechanism which targets the oil price and adjusts the quality ceiling to meet the target the stability of this controversial mechanism is compared to that of two alternatives one requires quantity control without any price targeting and the other is a synthesis of quantity control and the opec mechanisms all three mechanisms passed the stability test and the two alternatives give rise to some interesting policy implications practically considerations which involve the availability of specific information make opec s mechanism the most appropriate in terms of achieved targeted revenues the paper also offers a convergence strategy that speeds up the achievement of targeted revenues under opec s current mechanism

job selection and wages over the business cycle we consider a model with on the job search where current wages depend only on current aggregate labor market conditions and idiosyncratic match specic productivities we show theoretically that the model replicates the ndings in bils 1985 and beaudry and dinardo 1991 on the history dependence in wages we develop a method to measure match qualities in the data and show empirically that various variables summarizing past aggregate labor market conditions have explanatory power for current wages only because they are correlated with match qualities they lose any predictive power once match qualities are accounted for

optimal policies for inventory systems with lateral transshipments using lateral transshipments can be beneficial in order to improve service levels and to reduce system costs this paper deals with a single echelon inventory system with two identical locations demands are generated by stationary and independent poisson processes in general if a demand occurs at a location and there is no stock on hand the demand is assumed to be backordered or lost however in this paper lateral transshipments serve as an emergency supply in case of stock out in this paper the rule for lateral transshipments is given while the ordering policies for normal replenishments are optimized the transshipment rule is to always transship when there is a shortage at one location and stock on hand at the other first we assume that the locations apply r q policies for normal replenishments and show that the optimal policies are not necessarily symmetric even though the locations are identical this means that one cannot in general assume that the optimal policy is symmetric under symmetric assumptions second we relax the assumption of r q policies and derive the optimal replenishment policy using stochastic dynamic programming

opec and other commodity cartels a comparison abstract the economic literature provides specific characteristics for cartels although the theory of international cartels is not well developed in the literature and every cartel is unique some of these characteristics exist in each cartel this study investigates the existence of these characteristics in six known commodity cartels including opec in addition it compares the oil companies cartel the seven sisters to opec and summarizes the findings of opec econometric models developed in the literature in the last 25 years and concludes that the results do not support cartel or competitive models for opec although other cartels are more successful than opec many books and articles in economics use opec as a cartel example neither statistical tests nor theory support the popular use of opec as a cartel example indeed this article concludes that opec is composed of saudi arabia the dominant world producer plus several distinct sub groups and that separate models are required to explain the behavior of each assigning the power of some opec members to opec has caused confusion about its behavior recent opec success is attributed to political natural and technical capacity limitations in the oil fields that prevented countries from cheating on their quota in other words opec adherence to the quota except for saudi arabia is anything but voluntary

how to order and transship in multi location inventory systems the simulation optimization approach abstract the efficient control of multi location inventory systems with lateral transshipments has become increasingly important however existing models are analytically solvable only under simplifying assumptions there is a variety of heuristics to find approximate solutions but interdependencies between ordering and transshipment decisions for continuous time are not addressed thus we suggest using simulation optimization in our paper we describe a widely adaptable simulation model for mapping highly complex multi location inventory systems with lateral transshipments by applying this model to a special case from the literature and to some examples we show its validity and generality

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 impact of the asian crisis on the behavior of us and international petroleum prices the strong long run relationships among the petroleum spot and futures prices have weakened after the asian crisis as manifested in less co integration among these prices in the post crisis period the directional causal relationships have either changed the direction as in the case of wti crude or weakened somewhat as in the case of nymex gasoline and heating oil these changes should complicate the job of those who try to benefit from predicting the movements of petroleum prices after the asian crisis in the international gasoline spot markets movements in the nymex gasoline price are found to precede movements in the gulf coast and rotterdam gasoline prices in the pre crisis period and the movements of these prices and those of the singapore price in the post crisis period implying that the nymex price is the gasoline leader in both periods the monday friday day of the week effect is only significant for the nymex gasoline 1 month and 3 month futures prices and the gulf coast gasoline spot economic and political shocks related to the spot prices have greater impacts on all prices than shocks related to the futures prices regardless of the petroleum type and the time period

optimal and approximate policies in multiperiod multilocation inventory models with transshipments this paper examines the effects on the optimal ordering policy and its cost of allowing for interactions among retail outlets specifically transshipments are allowed as recourse actions occurring after demands are realized but before they must be satisfied the resultant savings in holding and shortage costs are balanced against the costs of transshipment a base stock ordering policy is optimal for this model if the final period base stock order up to point is nonnegative then it will be the base stock order up to point for all periods unfortunately it can be found analytically only for two special cases where either the cost parameters are equal at every outlet or there are only two outlets these two special cases are used to validate a heuristic solution technique employing monte carlo integration which is then compared to an easily calculated base policy in order to gauge the contribution of this model the additional savings from using this heuristic policy are significant particularly for problems with many retail outlets and low transshipment costs

implicit labor contracts and free entry the model investigated here is an adaptation of the free entry model introduced in kihlstrom laffont 1979 in that model the only labor market is one in which employers pay workers an ex ante guaranteed wage in the model of this paper there is also a spot market for labor in the earlier sections of the paper the existence of the equilibrium is established and its efficiency is investigated in this analysis it is assumed that all individuals are identical in the later sections we drop this assumption and investigate conditions under which employers are more risk averse than workers

real business cycles in this paper we demonstrate how certain very ordinary economic principles lead maximizing individuals to choose consumption production plans that display many of the characteristics commonly associated with business cycles our explanation is entirely consistent with i rational expectations ii complete current information iii stable preferences iv no technological change v no long lived commodities vi no frictions or adjustment costs vii no government viii no money and ix no serial dependence in the stochastic elements of the environment we also provide a completely worked out example of the type of artificial economy we have in mind the time series properties of the example exhibit some major features of observed business cycles although this type of model may not be capable of explaining all of the regularities in actual business cycles we believe that it provides a useful well defined benchmark for assessing the relative importance of factors e g monetary disturbances

cost parametric analysis of lateral transshipment policies in two echelon supply chains abstract in this paper we examine the cost effects of two lateral intra echelon transshipment approaches in a two echelon supply chain network with a single supply source at the higher echelon and multiple retail locations at the lower through a series of simulation experiments under different operating conditions an important finding is that either of the proposed lateral shipment approaches is considerably superior to a policy of no such shipments albeit at the expense of increased transportation activity further an ad hoc emergency transshipment approach appears to be significantly more effective in terms of several important criteria as compared to a more systematic transshipment technique based on stock level equalization

an inventory model with unidirectional lateral transshipments this paper deals with a continuous review inventory system with poisson demand in which lateral transshipments are allowed in case of a shortage at a location another location acts as a supplier if it is possible a common assumption in earlier papers is that transshipments are allowed between all locations this network configuration may however not be the best choice for many reasons one such reason is that it may be difficult to establish contracts between locations regarding the design of the transshipment policy another reason is that a system with many transshipment links is much more complex than a system with few transshipment links in this paper we study a system where transshipments are allowed only in one direction this may be a reasonable policy if the locations have very different backorder lost sales costs our approach is relatively simple and fast and works well in most cases

emergency lateral transshipments in a two location inventory system with positive transshipment leadtimes abstract we consider a single echelon continuous review inventory system for spare parts with two parallel locations each location faces independent poisson demand and backorders are allowed in this paper we consider the possibility of lateral transshipments between the locations the transshipment leadtime is positive and deterministic and there is an additional cost for making a transshipment we suggest a transshipment policy which is based on the timing of all outstanding orders and develop and solve a heuristic model by using theory and concepts from doubly stochastic poisson processes and also partial differential equations a simulation study indicates that our heuristic works very well and that the relative cost increase of disregarding the transshipment leadtime may be quite high our results also indicate that it is in general worth the effort of reducing the transshipment leadtime even if it is already relatively short

an index heuristic for transshipment decisions in multi location inventory systems based on a pairwise decomposition in multi location inventory systems transshipments are often used to improve customer service and reduce cost determining optimal transshipment policies for such systems involves a complex optimisation problem that is only tractable for systems with few locations consequently simple heuristic transshipment policies are often applied in practice this paper develops an approximate solution method which applies decomposition to reduce a markov decision process model of a multi location inventory system into a number of models involving only two locations the value functions from the subproblems are used to estimate the fair charge for the inventory provided in a transshipment this estimate of the fair charge is used as the decision criterion in a heuristic transshipment policy for the multi location system a numerical study shows that the proposed heuristic can deliver considerable cost savings compared to the simple heuristics often used in practice

accounting for the cyclical dynamics of income shares over the business cycle labor s share of output is negatively but weakly correlated with output and it lags output by about four quarters profit s share is strongly procyclical it neither leads nor lags output and its volatility is about four times that of output despite the importance of understanding the dynamics of income shares for understanding aggregate technology and the degree of competition in factor markets macroeconomics lacks models that can account for these dynamics this paper constructs a model that can replicate those facts we introduce costly entry of firms in a model with frictional labor markets and find a link between the ability of the model to replicate income shares dynamics and the ability of the model to amplify and propagate shocks that link is a countercyclical real interest rate a well known fact in u s data but a feature that models of aggregate fluctuations have had difficulty achieving

time to enter and business cycles abstract this paper examines a model in which market entry forms a business cycle propagation mechanism during expansionary periods new firms enter previously monopolized markets creating efficiency gains that amplify the effect of technology and fiscal policy shocks on employment market entry is delayed creating a dynamic pattern to output growth closer to that observed in the us economy than the standard rbc model