household saving in ldcs credit markets insurance and welfare some ways in which farmers in ldcs can protect their living standards against fluctuations in income are discussed after considering the theory of consumption under uncertainty when there is no or limited borrowing the case where some borrowing is allowed is also examined empirical evidence from some ldcs is used to look at i household borrowing and lending their importance and timing and their role in smoothing consumption and ii the life cycle behavior of consumption and income the results suggest that hump lifecycle saving is not likely to be a very important generator of wealth in ldcs and provide further evidence on the limited role of credit markets

life cycle consumption and hyperbolic discount functions abstract studies of animal and human behavior suggest that discount functions are approximately hyperbolic ainslie picoeconomics 1992 hyperbolic models explain a wide range of empirical anomalies including 1 missing precautionary savings effects 2 incongruence between the elasticity of intertemporal substitution and the inverse of the coefficient of relative risk aversion 3 consumption discontinuities at retirement 4 variation in patience over the life cycle 5 consumer self reports of undersaving 6 disproportionate retirement accumulation in illiquid assets 7 asset specific marginal propensities to consume and 8 declining national savings rates in developed countries hyperbolic models also provide a new framework for analyzing the welfare gains that come from pro saving policies like social security and tax deferred retirement accounts

wealth accumulation over the life cycle and precautionary savings this article constructs and simulates a life cycle model of wealth accumulation and estimates the parameters of the utility function the rate of time preference and the coefficient of risk aversion by matching the simulated median wealth profiles with those observed in the panel study of income dynamics and in the survey of consumer finances the estimates imply a low degree of patience and a high degree of risk aversion the results are used to study the importance of precautionary savings in explaining wealth accumulation they imply that wealth accumulation is driven mostly by precautionary motives at the beginning of the life cycle whereas savings for retirement purposes become significant only closer to retirement

analysis of tailored base surge policies in dual sourcing inventory systems we study a model of a firm managing its inventory of a single product by sourcing supplies from two supply sources a regular supplier who offers a lower unit cost and a longer lead time than a second emergency supplier a practically implementable policy for such a firm is a tailored base surge tbs policy allon g van mieghem ja 2010 global dual sourcing tailored base surge allocation to near and offshore production management sci 56 1 110 124 to manage its inventory under this policy the firm procures a constant quantity from the regular supplier in every period and dynamically makes procurement decisions for the emergency supplier allon and van mieghem describe this practice as using the regular supplier to meet a base level of demand and the emergency supplier to manage demand surges and they conjecture that this practice is most effective when the lead time difference between the two suppliers is large we confirm these statements in two ways first we show the following analytical

inventory management for stochastic lead times with order crossovers we study the impact of stochastic lead times with order crossover on inventory costs and safety stocks in the order up to out policy to motivate our research we present global logistics data which violates the traditional assumption that lead time demand is normally distributed we also observe that order crossover is a common and important phenomenon in real supply chains we present a new method for determining the distribution of the number of open orders using this method we identify the distribution of inventory levels when orders and the work in process are correlated this correlation is present when demand is auto correlated demand forecasts are generated with non optimal methods or when certain ordering policies are present our method allows us to obtain exact safety stock requirements for the so called proportional order up to pout policy a popular implementable linear generalization of the out policy we highlight that the out replenishment policy is not cost optimal in global supply chains as we are able to demonstrate the pout policy always outperforms it under order cross over we show that unlike the constant lead time case minimum safety stocks and minimal inventory variance do not always lead to minimum costs under stochastic lead times with order crossover we also highlight an interesting side effect of minimizing inventory costs under stochastic lead times with order crossover with the pout policy an often significant reduction in the order variance

household saving micro theories and micro facts in this survey we review the recent theoretical and empirical literature on household saving and consumption the discussion is structured around a list of motives for saving and how well the standard theory captures these motives we show that almost all of the motives for saving that have been suggested in the informal saving literature can be captured in the standard optimizing model particular attention is given to recent work on the precautionary motive and its implications for saving and consumption behavior we also discuss the behavioral or psychological approach that eschews the use of standard optimization techniques and focuses instead on direct consideration on saving we provide a section on facts who save and how much we then discuss informally the recent decline in the u s saving rate and whether the theory is of much use in understanding this and other changes in aggregate saving rates over time we do not find any convincing explanation for the change in saving rates we also discuss some analyses of saving behavior over the life cycle addressing such questions as whether households save enough for retirement and whether the consumption patterns of older households can be rationalized within a simple life cycle model we also review a great number of studies of the consumption euler equations based on our analysis of the studies cited we conclude that there is still mixed evidence that consumption is excessively sensitive to income we also examine in depth the recent empirical literature on the precautionary motive we conclude that although some households do seem to have a significant precautionary motive at some points in their life cycle this motive is not so strong empirically as some investigators suggest

home or overseas an analysis of sourcing strategies under competition motivated by the recent backshoring trend this paper studies a sourcing game where competing firms may choose between efficient sourcing e g sourcing from overseas and responsive sourcing e g sourcing from a home country efficient sourcing usually provides a cost advantage whereas responsive sourcing allows a firm to obtain more accurate demand information when making procurement decisions by characterizing the equilibrium outcome we find some interesting results driven by the strategic interaction between the firms first a firm may still use efficient sourcing in equilibrium even when the cost advantage associated with efficient sourcing does not exist this is because the firm can dampen competition by reducing the correlation between its own demand information and the competitor s second a cost hike in efficient sourcing e g the rising labor cost in asia may benefit all the firms in the industry the reason is that the cost hike may alleviate competition by inducing a new equilibrium sourcing structure this paper also sheds some light on the recent backshoring trend first our analysis indicates that more firms will shift from efficient sourcing to responsive sourcing in equilibrium i e backshore if the market size shrinks the demand becomes more volatile or the sourcing costs rise simultaneously second a firm s backshoring behavior reduces the competition on the cost dimension but it also has an ambiguous informational impact on the other firms in the market in particular some firms may benefit from increased correlation of their demand information under cournot competition with substitutable products overall the backshoring behavior can be beneficial to all the firms sticking to their original sourcing strategies under certain conditions this paper was accepted by martin lariviere operations management

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

how do behavioral assumptions affect structural inference evidence from a laboratory experiment we use a laboratory experiment to investigate the effect that assuming rational expectations has on structural inference on a dynamic discrete choice decision problem our experimental design induces preferences up to each subject s subjective rates of time preference leaving unrestricted only this parameter and the decision rule that the subject uses in solving the problem we analyze the data under the assumption that all subjects use the rational expectations decision rule and also under weaker behavioral assumptions that allow for heterogeneity in the way people form decisions we find no evidence that assuming rational expectations distorts inferences about the cross sectional distribution of discount rates

rules of thumb versus dynamic programming this paper studies decision making with rules of thumb in the context of dynamic decision problems and compares it to dynamic programming a rule is a fixed mapping from a subset of states into actions rules are compared by averaging over past experiences this can lead to favoring rules which are only applicable in good states correcting this good state bias requires solving the dynamic program we provide a generalframework and characterize the asymptotic properties we apply it to provide a candidate explanation for the sensitivity of consumption to transitory income jel eoo c63 c61 e21

farming the tax code the impact of high marginal tax rates on agricultural tax shelters surprisingly little scholarly work has examined the practice of farming the tax code in which accounting losses on agricultural investments are used to shelter other income from taxation economic theory suggests that the amount of investment in agricultural tax shelters is positively related to the marginal tax rate this hypothesis is empirically investigated using a sample of federal individual income tax returns filed for 1983 both the probability of reporting a farm tax loss and the amount of farm losses are increased by a rise in the marginal tax rate especially among upper income taxpayers

saving and liquidity constraints this paper is concerned with the theory of saving when consumers are not permitted to borrow and with the ability of such a theory to account for some of the stylized facts of saving behavior the models presented in the paper seem to account for important aspects of reality that are not explained by traditional life cycle models copyright 1991 by the econometric society

psychology and savings policies many observers of the current economic scene are concerned about the low rate of personal saving in the united states one well known researcher laurence kotlikoff 1992 calls the situation a crisis he proposes that each american worker receive an annual statement from the social security administration with projected benefits upon retirement arguing that if each of us got this statement our attention would be caught and perhaps our psychology of saving which is in such urgent need of redress would really change p 107 i agree with the thrust of kotlikoff s recommendations and join him in applauding steps that will alter the general public s psychology of saving however as economists we need to recognize that the economic theory of saving is similarly in urgent need of redress if we are to understand why people are saving so little and are to make helpful recommendations as to how to get people to save more we have to incorporate more of the psychology of saving into our economic theories kotlikoff s policy proposal while a sensible one highlights the growing gap between theory and policy prescription in this domain if households are acting in accordance with the life cycle theory of saving then undersaving is impossible so why do they need to have their psychology redressed and how does this psychology fit into the model this example reflects an increasing frustration in the economics community about personal saving many observers have come to the conclusion that the low saving rate represents an important problem on two fronts macroeconomists worry that the low saving rate will produce too little investment and microeconomists worry that individuals particularly the baby boomers are not putting enough away to finance a satisfactory lifestyle in retirement these are serious concerns however the frustration comes from the realization that even if there was agreement that the saving rate needs to go up economic theory offers little help in constructing a solution in the standard life cycle framework the only policy variable is the after tax rate of return to saving yet it is well known that the theory does not specify the sign of the relationship between the saving rate and the interest rate raising the interest rate increases the returns to saving but decreases the amount of saving necessary to yield any given future consumption level furthermore empirical estimates offer little help most studies are unable to reject the hypothesis that the elasticity of personal saving with respect to the interest rate is zero clearly this is frustrating the theory only gives us one lever to use and we don t know whether to push or pull with this background i wish to supply what should be considered good news the theory is misspecified life cycle models of saving fail to describe actual household saving in three important ways this failure of the theory is good news because by incorporating some basic psychology we can enrich the theory and generate specific policy recommendations in this paper i will begin by characterizing the problems with the theory and then go on to discussing the implications of modifying the theory

on the consequences of demographic change for rates of returns to capital and the distribution of wealth and welfare in the industrialized world the population is aging over time reducing the fraction of the population in working age consequently labor is expected to be scarce relative to capital with an ensuing decline in the real return on capital this paper uses demographic projections together with a large scale multi country overlapping generations model with uninsurable idiosyncratic uncertainty to quantify the distributional and welfare consequences of these changes in factor prices induced by the demographic transition in our model capital can freely flow between different regions in the oecd the u s the eu and the rest of the oecd thus international capital flows may in principle mitigate the decline in rates of returns one would expect in the u s if it were a closed economy we find exactly the opposite in the u s as an open economy rates of return are predicted to decline by 86 basis points between 2005 and 2080 if the u s were a closed economy this decline would amount to only 78 basis points this result is due to the fact that other regions in the oecd will age even more rapidly therefore the u s is importing the more severe aging problem from these regions especially europe a similar conclusion is reached if we let capital flow freely between the oecd and the rest of the world row while row currently has a younger population structure it is predicted to age even more severely in the next decades giving rise to an even more pronounced decline in world rates of return to capital in order to evaluate the welfare consequences of the demographic transition we ask the following hypothetical question suppose a household economically born in 2005 would live through the economic transition with changing factor prices induced by the demographic change but keeping her own survival probabilities constant at their 2005 values how would its welfare have changed relative to a situation without a demographic transition we find that households experience significant welfare losses due to the demographic transition in the order of 2 5 of consumption depending on their initial productivity level and the design of the pension system these losses are mainly due to the fact that lower future returns to capital make it harder for households to save for retirement on the other hand if the oecd suddenly opens up to row in 2005 and row has higher returns to capital before the world capital market integration then these losses are reduced to 1 5 2 5

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

are americans saving optimally for retirement we solve each household s optimal saving decisions using a life cycle model that incorporates uncertain lifetimes uninsurable earnings and medical expenses progressive taxation government transfers and pension and social security benefits with optimal decision rules we compare household by household wealth predictions from the life cycle model using a nationally representative sample we find making use of household specific earnings histories that the model accounts for more than 80 percent of the 1992 cross sectional variation in wealth fewer than 20 percent of households have less wealth than their optimal targets and the wealth deficit of those who are undersaving is generally small

wealth weather risk and the composition and profitability of agricultural investments despite the growing evidence that farmers in low income environments are risk averse there has been little empirical evidence on the importance of risk in shaping the actual allocation of production resources among farmers differentiated by wealth the authors use panel data on investments in rural india to examine how the composition of productive and nonproductive asset holdings varies across farmers with different levels of total wealth and across farmers facing different degrees of weather risk income variability is a prominent feature of the experience of rural agents in low income countries the authors report evidence based on measures of rainfall variability that the agricultural investment portfolio behavior of farmers in such settings reflects risk aversion due evidently to limitations on consumption soothing mechanisms such as crop insurance or credit markets the authors results suggest that uninsured weather risk is a significant cause of lower efficiency and lower average incomes a one standard deviation decrease in weather risk measured by the standard deviation of the timing of the rainy season would raise average profits by up to 35 percent among farmers in the lowest wealth quartile moreover rainfall variability induces a more unequal distribution of average incomes for a given distribution of wealth wealthier farmers are willing to absorb significant risk without giving up profits to reduce production risk smaller farmers have to invest their limited wealth in ways that reduce their exposure to risk at the cost of lower profit rates the authors found that at high levels of rainfall variability differences in rates of profit per unit of agricultural assets were similar across classes of wealth but over the sample range of rainfall variability these rates of profit were always higher for the poorer farmers than for the wealthier ones suggesting that the disadvantages of small farmers in risk diffusion are more than offset by their labor cost advantage

the behavioral life cycle hypothesis self control mental accounting and framing are incorporated in a behavioral enrichment of the life cycle theory of saving called the behavioral life cycle blc hypothesis the key assumption of the blc theory is that households treat components of their wealth as nonfungible even in the absence of credit rationing specifically wealth is assumed to be divided into three mental accounts current income current assets and future income the temptation to spend is assumed to be greatest for current income and least for future income considerable empirical support for the blc theory is presented primarily drawn from published econometric studies

do investors respond to tax reform evidence from a natural experiment in germany abstract we present new evidence for the importance of taxation in households investment decisions a difference in difference analysis shows that a tax reform in germany which revoked the tax exemption of life insurance returns triggered a significant increase in demand prior to the reform

attainable non optimality or unattainable optimality a new approach to stochastic life cycle when future income is uncertain the standard model of stochastic life cycle behavior does not provide an operatio nal basis for consumer choice because it is too complex to be solved either analytically or intuitively by the human brain even if computer assisted this paper proposes an alternative model of intertemporal decision making that takes full account of the future including future uncertainty but which is analytically tractable t he model is applied to some illustrative examples copyright 1993 by royal economic society

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

baby boomer retirement security the roles of planning financial literacy and housing wealth abstract we compare wealth holdings across two cohorts of the health and retirement study the early baby boomers in 2004 and individuals in the same age group in 1992 levels and patterns of total net worth have changed relatively little over time though boomers rely more on housing equity than their predecessors most important planners in both cohorts arrive close to retirement with much higher wealth levels and display higher financial literacy than non planners instrumental variables estimates show that planning behavior can explain the differences in savings and why some people arrive close to retirement with very little or no wealth

habits and time preference this paper proposes a utility function incorporating both habit formation and an endogenous rate of time preference in a manner consistent with the intuition of irving fisher regarding the influence of past consumption on impatience it is shown that the ne w specification is tractable and generates new predictions in the cont ext of three model economies 1 a closed economy with heterogeneous agents 2 a small open economy with one traded good and one nontra ded good and 3 a small open economy with a traded good and domestic money copyright 1993 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

saving in the world abstract this paper presents new evidence on the behavior of saving in the world by extending previous empirical research in several dimensions after extensively surveying the relevant theoretical and empirical literature the paper reports estimates of saving determinants relying on the newly constructed and largest available database covering 165 countries over 1981 2012 the empirical specification includes determinants not considered in the literature explores differences in saving behavior nesting the 2008 10 crisis period and four different country groups searches for commonalities across key saving aggregates national private household and corporate saving rates and is subject to a robustness analysis based on different estimation techniques the results confirm in part existing research but also shed light on some ambiguous or contradictory findings and highlight the role of neglected determinants compared to the literature we find a larger number of significant determinants changes across periods and country groups and similarities across different saving aggregates

new policies for the stochastic inventory control problem with two supply sources we study an inventory system under periodic review in the presence of two suppliers or delivery modes the emergency supplier has a shorter lead time than the regular supplier but the unit price he offers is higher excess demand is backlogged we generalize the recently studied class of dual index policies veeraraghavan s a scheller wolf 2008 now or later dual index policies for capacitated dual sourcing systems oper res 56 4 850 864 by proposing two classes of policies the first class consists of policies that have an order up to structure for the emergency supplier we provide analytical results that are useful for determining optimal or near optimal policies within this class this analysis and the policies we propose leverage our observation that the classical lost sales inventory problem is a special case of this problem the second class consists of policies that have an order up to structure for the regular supplier here we derive bounds on the optimal order quantity from the emergency supplier in any period and use these bounds for finding effective policies within this class finally we undertake an elaborate computational investigation to compare the performance of the policies we propose with that of dual index policies one of our policies provides an average cost saving of 1 1 over the best dual index policy and has the same computational requirements another policy that we propose has a cost performance similar to the best dual index policy but its computational requirements are lower

a periodic review inventory system with emergency replenishments this paper proposes and analyzes a periodic review inventory system with two replenishment modes regular orders are placed periodically following a base stock policy on inventory position and arrive at the stocking location after a deterministic lead time the location also has the option of placing emergency orders characterized by a shorter lead time but higher acquisition cost in case of imminent stockouts thus at some appropriate time in the replenishment cycle the necessity and size of an emergency order is determined according to a base stock policy on net stock the timing of the emergency order is such that this order arrives and can be used to satisfy the demand in the time period just before the arrival of a regular order when the likelihood of a stockout is highest an approximate cost model is developed which can easily be optimized with respect to the order up to parameters this model is used as the basis for a heuristic algorithm which leads to solutions that are very close to the exact optimal solutions determined through simulation it is shown that the proposed system offers substantial cost savings relative to a system without the emergency replenishment option

rules of thumb in life cycle saving decisions we analyse life cycle saving decisions when households use simple heuristics or rules of thumb rather than solve the underlying intertemporal optimisation problem we simulate life cycle saving decisions using three simple rules and compute utility losses relative to the solution of the optimisation problem our simulations suggest that utility losses induced by following simple decision rules are relatively low moreover the two main saving motives reflected by the canonical life cycle model long run consumption smoothing and short run insurance against income shocks can be addressed quite well by saving rules that do not require computationally demanding tasks such as backwards induction

the sensitivity of consumption to transitory income estimates from panel data on households we investigate the stochastic relation between income and consumption specifically consumption of food within a panel of about 2 000 households our major findings are 1 consumption responds much more strongly to permanent than to transitory movements of income 2 the response to transitory income is nonetheless clearly positive 3 a simple test independent of our model of consumption rejects a central implication of the pure life cycle permanent income hypothesis the observed covariation of income and consumption is compatible with pure life cycle permanent income behavior on the part of80 percent of families and simple proportionality of consumption and income among the remaining 20 percent as a general matter our findings support the view that families respond differently to different sources of income variations in particular temporary income tax policies have smaller effects on consumption than do other more permanent changes in income of the same magnitude this abstract was borrowed from another version of this item

wage risk and employment risk over the life cycle we specify a structural life cycle model of consumption labour supply and job mobility in an economy with search frictions that allows us to distinguish between different sources of risk and to estimate their effects the sources of risk are shocks to productivity job destruction the process of job arrival when employed and unemployed and match level heterogeneity our model allows for four main social insurance programmes in contrast to simpler models that attribute all income fluctuations to shocks our framework allows us to disentangle the effects of the shocks from the responses to these shocks estimates of productivity risk once we control for employment risk and for individual labour supply choices are substantially lower than estimates that attribute all wage variation to productivity risk increases in productivity risk impose a considerable welfare loss on individuals and induce substantial precautionary saving increases in employment risk have large effects on output and primarily through this channel affect welfare the welfare value of government programs such as food stamps which partially insure productivity risk is greater than the value of unemployment insurance which provides partial insurance against employment risk and no insurance against persistent shocks

the life cycle model of consumption and saving a central implication of life cycle models is that agents smooth consumption we review the empirical evidence on smoothing at frequencies from within the year up to across a lifetime we find that life cycle models particular those which incorporate realistic features of markets and goods have more empirical successes than failures we also show that some apparent deviations from theoretical predictions imply very small welfare losses for agents finally we emphasize that the coherence of life cycle models imposes an important discipline when incorporating new features into models

optimal policy structure characterization for a two period dual sourcing inventory control model with forecast updating a proposed single product stochastic two period inventory control model combines demand forecast updating with the flexibility of two supply sources demand is modeled by two independent random variables over a two period selling season at the beginning of the first period two quantities are ordered using two different supply options a local supplier who delivers the ordered quantity immediately and a second supplier who delivers the ordered quantity at the beginning of the second period the local supplier charges a higher cost per ordered unit the model considers an initial inventory so the decision maker has an opportunity at the beginning of the first period to return part of the available inventory to the supplier or sell it in a parallel market at the end of the first period any unsatisfied demand is backlogged to be satisfied in the next period at the beginning of the second period exogenous market information updates the second period demand forecast according to this updated forecast and the actual inventory level an additional quantity is ordered using the local procurement source or another quantity is returned to the supplier or sold in a parallel market with a dynamic programming approach this research exhibits the structure of the optimal policy characterized by order up to and salvage up to levels the findings provide the structure of the second period conditional optimal policy and analytical insights that characterize the first period optimal policy furthermore a numerical study reveals the impact of information quality on the optimal policy and the trade off between the two procurement options

racial differences in homeownership and housing wealth 1970 1986 racial differences in homeownership and housing wealth 1970 1986 black couples are found to own a disproportionately low share of aggregate housing wealth in the united states because they are less likely than whites to be homeowners and because black owned houses have lower market values than white owned houses probability of ownership and house value equations corrected for selectivity bias are estimated with national data for 1970 1980 and 1986 trends in racial differences in homeownership and house value are identified and reasons for their existence are investigated i introduction the wage gap between blacks and whites has been the subject of many labor market studies during the last two decades these studies spawned similar analyses of racial differences in other markets such as housing concern over the black white differential in economic well being continues today with recent attention focusing on the wealth gap between blacks and whites andrew brimmer 1988 points out that blacks owned only 3 0 percent of accumulated wealth in the united states in 1984 even though blacks received 7 6 percent of total money income that year and they comprised 11 percent of all households 1 the equity accumulated in homes constituted the most important form of wealth held by blacks but even so the black share of home equity was only 4 4 percent of the total the value of black owned housing will be disproportionately low if a blacks are not as likely as whites to own homes and b blacks houses are relatively less valuable than whites houses in this paper we investigate both of these possibilities with national data on black and white households covering the period 1970 86 2 existing research has concentrated primarily on racial differences in the probability of homeownership with an eye toward determining the extent of discrimination 3 at least two prominent congressmen joseph kennedy of massachusetts and henry gonzalez of texas have charged that government regulators routinely allow discrimination in home mortgage lending because most studies have relied on data from the 1960s and early 1970s often covering only certain metropolitan areas no reliable estimates of the national trend in black homeownership and housing market discrimination during more recent years exist the question of how much housing blacks consume relative to whites given the decision to own has received only scant attention in the literature yet both decisions influence wealth distribution our study compares the racial differentials in these two dimensions of the housing choice ownership and value a basic hypothesis of the paper is that house value differentials by race will be larger than homeownership differentials by race since the factors that determine house prices are more numerous and probably more susceptible to discriminatory influence than the conditions that influence the decision to own rather than rent ii a model of the homeownership choice this section describes a model of the homeownership decision that can be applied to available data the model is similar to those of previous studies in that it relates the probability of owning a home to several explanatory variables reflecting economic demographic and locational characteristics of the household it differs in an important respect however in that it is estimated on a sample that contains only husband and wife households 4 most earlier studies that have used samples drawn from the entire population have controlled for different household types e g single female headed widowed by means of dummy variables this procedure generally constrains the impact of race on the housing choice to be equal for all household types in addition mcdonald 1974 has pointed out that the current values of variables such as income and labor market activity are more apt to misrepresent their permanent levels for single person or female headed households

managing global sourcing inventory performance the use of global suppliers has increased considerably over the last three decades operations management theory establishes that global sourcing requires more units of inventory but since these units are often procured at a lower cost from global suppliers the capital invested in inventory and the consequent financial burden may increase or decrease with global sourcing this study provides rigorous firm level empirical evidence that links the global sourcing practices of public u s firms and their inventory investments we process bill of lading manifests customs forms to extract information on over half a million sea shipments from global suppliers to u s public firms and link this information with quarterly financial data from the compustat database we provide stylized facts on the participation of different firms and sectors in global trade using a simultaneous equation model we find that an increase in global sourcing results in an increase in inventory investment a 10 shift in sourcing from domestic to global suppliers increases the inventory investment by 8 8 for an average firm in our sample we also find that increasing the number of suppliers can mitigate this increase in inventory investment for example going from single to dual sourcing reduces inventory investment by about 11 we illustrate the use of our estimates to identify the impact of changing global sourcing strategy on inventory investment and operational performance metrics this paper was accepted by martin lariviere operations management

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

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

multiechelon procurement and distribution policies for traded commodities we consider a firm that procures and distributes a commodity from spot and forward markets under randomly fluctuating prices the commodity is distributed downstream to a set of nonhomogeneous retailers to satisfy random demand we formulate a model that allows one to compute approximate but near optimal procurement and distribution policies for this system and we explore the value of the commodity s market in providing managers with a additional flexibility in procurement and b information on price dynamics generated through the trading of futures contracts our results indicate that the presence of the commodity market and the information that it conveys may lead to significant reductions in inventory related costs however to obtain these benefits both the spot procurement flexibility and the term structure of prices generated by the commodity market must be incorporated in the formulation of the operating policy managerial insights on the procurement strategy as a function of variability in prices and demand are also discussed this paper was accepted by john birge focused issue editor

estimating and decomposing changes in the white black homeownership gap from 2005 to 2011 this study evaluates the effects of the recent us housing bust on the white black homeownership gap by estimating and decomposing the changes in the distribution of the gap between 2005 and 2011 our analysis shows that the housing bust did not affect the homeownership gap uniformly in fact we find that the gap decreased for households that were the least likely to own and remained unchanged for households that were the most likely to own and that black households with around a 50 probability of homeownership were especially vulnerable to the crisis we also find that the contribution of the residual gap was modest changes in the white black homeownership gap over the sample period are mainly attributed to changes in household income whether the household earned dividend interest or rental income and marital status with the extent of their respective influences varying over the homeownership distribution our empirical approach reveals distributional information on the determinants of the changes

the sensitivity of tests of the intertemporal allocation of consumption to near rational alternatives suppose a consumer sets consumption equal to income each period rather than following the optimal permanent income decision rule how much utility does he lose this paper finds that the answer is typically less than 10 cents 1 per quarter in environments specified by popular tests on aggregate data it includes calculations of the costs of excess sensitivity and excess smoothness to income and interest rate changes and the costs of ignoring information it concludes that the theory does not make predictions for aggregate tests that are robust to small costs such as information or transactions copyright 1989 by american economic association

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