defining chronic poverty comparing different approaches in this study we discuss two methods commonly used in the literature to measure chronic poverty the permanent income approach where the chronically poor are those whose mean income over time is below the poverty line and the spells approach where the chronically poor are those households who are below the poverty line half of the time or more we check the differences between these two methods considering also several household characteristics the index we use is that of foster greer and thorbecke fgt with and when each method identifies the chronically poor which could be different individuals by each method and shows the percentage of the chronically poor while when the methods also take into account the depth of poverty our main goal is to show the differences between the two methods so that policymakers would have different perspectives on the problem of chronic poverty and could make decisions on this basis the results show that in the data used the permanent method and the spells

state alcohol policies teen drinking and traffic fatalities this empirical study evaluates the policy responsiveness of teen drinking in models that can condition on the unobserved state specific attributes that may have biased conventional evaluations the results demonstrate that cross state heterogeneity can be important and that beer taxes have relatively small and statistically insignificant effects on teen drinking models of youth traffic fatalities also indicate that the conventional beer tax elasticities are not robust to additional controls for omitted variables the importance of these omitted variables is illustrated by a counterfactual which compares models of nighttime fatalities to those that occur in the daytime when the rate of alcohol involvement is substantially lower

chronic poverty in the united states this paper proposes a method of measuring chronic and transitory poverty using an axiomatically sound additively decomposable index of aggregate poverty our approach is contrasted with alternative methods of measuring poverty persistence we use our method to measure chronic and transitory poverty in the united states during the 1980s and late 1970s and find that chronic poverty is a more serious problem than previously thought between the late 1970s and mid 1980s poverty not only increased it became more chronic and less transitory in nature this is true for the population as a whole and for some but not all of the subpopulations we considered the latter were defined according to race type of social unit and educational qualifications of the head of the social unit all empirical analyses are based on data from the panel study of income dynamics

slipping into and out of poverty the dynamics of spells this paper examines the dynamics of poverty previous analyses have examined either fluctuations in the male heads earnings or the frequency of poverty periods over a fixed time frame our approach depends on a definition of spells of poverty using this methodology we find that the majority of poor persons at any time are in the midst of a rather long spell of poverty the methodology also allows us to estimate that less than 40 percent of poverty spells begin because of a drop in the heads earnings while 60 percent of the spells end when the heads earnings increase thus researchers must focus on household formation decisions and on the behavior of secondary family members there has been a dramatic resurgence recently of discussion of the underclass the discussion is reminiscent of debates about poverty during the 1960s when the notions of a culture of poverty particularly as popularized by michael harrington s other america 1962 dominated both intellectual and policy thinking the idea of an underclass seems inconsistent however with much of the research on the dynamics of poverty during the 1970s that research using new longitudinal data seemed to show that the bulk of the poor were poor for only a few years the research also showed that the poor were a very heterogeneous group including a small minority of persistently poor the persistence of poverty is of interest both for understanding the phenomenon and for developing policy claims about dependency and separate life styles among the poor rest on assumptions about the long term nature of poverty questions

do changes in the labour market take families out of poverty determinants of exiting poverty in brazilian metropolitan regions using survival models we test whether short term changes in the labour market affect poverty duration data are from the brazilian monthly employment survey such a monthly dataset permits more accurate estimations of events than using annual data but its panel follows households for a short period then methods that control for both right and left censoring should be used the results are as follows households with zero income are not those with the lowest chances of exiting changes in aggregate unemployment do not affect poverty duration and increasing wages in the informal sector has a negative effect on poverty duration

explaining occupational sex segregation and wages findings from a model with fixed effects does segregation arise because female occupations have financial advantages for women planning to spend some time as homemakers as human capital theorists claim do male occupations have more onerous working conditions that explain their higher earnings as the neoclassical notion of compensating differentials suggests or do female occupations have low wages that are depressed by the sort of discrimination at issue in comparable worth as sociologists have argued to answer these questions the authors use a model with fixed effects to predict the earnings of young men and women from a pooled cross section time series of the national longitudinal survey analyses are undertaken for both blacks and whites a fixed effects model is useful for answering these questions because it corrects for the selection bias that results from the tendency of persons who differ on stable characteristics that are unmeasured but affect earnings to select themselves into different occupations the authors find little evidence that female occupations provide either low penalties for intermittent employment at high starting wages the advantages human capital theorists have argued them to have rather there is evidence of pay discrimination against men and women in predominantly female occupations implications for economic and sociological theories of labor markets are discussed authors

consistency of higher order risk preferences risk aversion a second order risk preference is a time proven concept in economic models of choice under risk more recently the higher order risk preferences of prudence third order and temperance fourth order also have been shown to be quite important while a majority of the population seems to exhibit both risk aversion and these higher order risk preferences a significant minority does not we show how both risk averse and risk loving behaviors might be generated by a simple type of basic lottery preference for either 1 combining good outcomes with bad ones or 2 combining good with good and bad with bad respectively we further show that this dichotomy is fairly robust at explaining higher order risk attitudes in the laboratory in addition to our own experimental evidence we take a second look at the extant laboratory experiments that measure higher order risk preferences and we find a fair amount of support for this dichotomy our own experiment also is the first to look beyond fourth order risk preferences and we examine risk attitudes at even higher orders

reduction of the value of information sharing as demand becomes strongly auto correlated information sharing has been identified in the academic literature as one of the most important levers to mitigate the bullwhip effect in supply chains a highly cited article on the bullwhip effect has claimed that the percentage inventory reduction resulting from information sharing in a two level supply chain when the downstream demand is autoregressive of order one is an increasing function of the autoregressive parameter of the demand in this paper we show that this is true only for a certain range of the autoregressive parameter and there is a maximum value beyond which the bullwhip ratio at the upstream stage is reduced and the percentage inventory reduction resulting from information sharing decreases towards zero we also show that this maximum value of the autoregressive parameter can be as high as 0 7 which represents a common value that may be encountered in many practical contexts this means that large benefits of information sharing cannot be assumed for those stock keeping units skus with highly positively auto correlated demand instead equally careful analysis is needed for these items as for those skus with less strongly auto correlated demand

design for postponement a comprehensive characterization of its benefits under unknown demand distributions recent papers have developed analytical models to explain and quantify the benefits of delayed differentiation and quick response programs these models assume that while demands in each period are random they are independent across time and their distribution is perfectly known i e sales forecasts do not need to be updated as time progresses in this paper we characterize these benefits in more general settings where parameters of the demand distributions fail to be known with accuracy or where consecutive demands are correlated here it is necessary to revise estimates of the parameters of the demand distributions on the basis of observed demand data we analyze these systems in a bayesian framework assuming that our initial information about the parameters of the demand distributions is characterized via prior distributions we also characterize the structure of close to optimal ordering rules in these systems for a variety of types of order cost functions

approximations of dynamic multilocation production and inventory problems consider a central depot or plant which supplies several locations experiencing random demands orders are placed or production is initiated periodically by the depot the order arrives after a fixed lead time and is then allocated among the several locations the depot itself does not hold inventory the allocations are finally received at the demand points after another lag unfilled demand at each location is backordered linear costs are incurred at each location for holding inventory and for backorders also costs are assessed for orders placed by the depot the object is to minimize the expected total cost of the system over a finite number of time periods this system gives rise to a dynamic program with a state space of very large dimension we show that this model can be systematically approximated by a single location inventory problem all the qualitative and quantitative results for such problems can then be applied

inventory dynamics in process industries an empirical investigation process industry firms have thrived in recent decades but changes in the markets are currently putting both growth and profitability at risk in this context inventory management is increasingly viewed as an essential lever for creating a sustainable competitive advantage despite this many firms struggle to implement best practices because of industry specific constraints this research explores how seven fundamental characteristics of process industries drive inventory performance we empirically investigate four process industries and four peer industries using financial accounting credit rating stock market and trading data and implement a seemingly unrelated regression sur equations model our results show that capital intensity capital costs transportation costs delivery time price volatility demand uncertainty and gross margin directly affect a company s degree of freedom in terms of inventory management and illustrate that inventory management in process industries follows different dynamics this study enhances the understanding of inventory drivers and gives practitioners a tool to guide future improvement efforts

has children s poverty become more persistent iffood stamp benefits are counted as income there is little change in estimates ofpersistent povertyfor children between the late 1960s and early 1980s however the absence of change in persistent poverty masks a number of important changes in the demographic and statistical structure ofpersistent poverty these changes include increasing inequality in the distribution of permanent socioeconomic position greater dependence on social assistance and the more familiar demographic changes such as increased numbers of single parent families higher educational attainments of parents and decline in family size

the effect of cognitive load on economic decision making a survey and new experiments abstract psychologists and economists have examined the effect of cognitive load in a variety of situations from risk taking to snack choice we review previous experiments that have directly manipulated cognitive load and summarize their findings we report the results of two new experiments where participants engage in a digit memorization task while simultaneously performing a variety of economic tasks including 1 choices involving risk 2 choices involving intertemporal substitution 3 choices with anchoring effects 4 choices over healthy and unhealthy snacks and 5 math problems we find that higher cognitive load reduces numeracy as measured by performance in math problems moreover within subject analysis indicates that cognitive load leads to more risk averse behavior more impatience over money and nominally more likelihood to anchor we do not find any evidence that cognitive load increases impatience over consumption goods or unhealthy snack choices exploiting the panel nature of our data set we find that those individuals who are most sensitive to cognitive load as measured by a large drop in their own math performance across 1 and 8 digit memorization treatments are driving much of the effect

the effects of alcohol use on economic decision making in a controlled laboratory experiment we study the causal effect of alcohol on economic decision making a treatment group was given a dose of alcohol designed to target a blood alcohol concentration bac of 0 08 while the bac of those in the control group remained 0 00 we investigate the behavior of control and treatment groups in the following types of tasks math uncertainty overconfidence strategic games food choice anchoring and altruism our results indicate that alcohol consumption has little systematic effect on economic behavior at least for the bac level considered further there is little evidence that alcohol differentially impacts the choices of male and female subjects

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

a two echelon allocation model and the value of information under correlated forecasts and demands abstract in this article we explore the effects of incorporating forecasts explicitly in a two echelon allocation model which consists of a central depot and several retailers in particular we investigate the possible benefits on the system costs and inventory levels the depot does not hold any inventory and the demand is observed only at the retailers under a general correlated demand forecast structure we obtain the approximate system wide order up to level and the expected system cost in order to assess the value of information provided by keeping track of the forecasts we construct a comparable inventory system operating under a standard demand model we demonstrate that the standard demand model results in higher order up to levels and higher system costs

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

decision environment effects on intertemporal financial choices how relevant are resource depletion models a large literature in psychology studies the effects of the immediate decision environment on behavior and conceptualizes both cognitive capacity and self control as scarce resources that can be depleted by recent use and replenished by factors like rest and nutrition we assess the relevance of resource depletion models for intertemporal financial decisions by estimating the effects of three interventions prior impulse controlling activity consumption of a sugared drink and consumption of a placebo sugar free drink on intertemporal monetary choices in a cash advance framework these manipulations have large impacts on the demand for advances but contrary to resource based models prior impulse controlling activity and placebo drink consumption increase patience to understand these effects we estimate treatment effects on the three parameters of a decision utility model for every subject in our sample all treatments reduce utility curvature and present bias and these movements are highly correlated together we argue that these patterns suggest that the treatments are acting not on subjects fundamental utility parameters but on subjects tendencies to frame financial decisions narrowly within the frame of the lab experiment versus broadly in the context of their other financial options thus while decision environments have large effects on intertemporal financial decisions both the direction and the mechanisms underlying these effects appear to be quite different from those suggested by resource depletion models

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

inventory performance under staggered deliveries and autocorrelated demand production plans often span a whole week or month even when independent production lots are completed every day and service performance is tallied daily such policies are said to use staggered deliveries meaning that the production rate for multiple days are determined at a single point in time assuming autocorrelated demand and linear inventory holding and backlog costs we identify the optimal replenishment policy for order cycles of length p with the addition of a once per cycle audit cost we optimize the order cycle length p via an inverse function approach in addition we characterize periodic inventory costs availability and fill rate as a consequence of staggering deliveries the inventory level becomes cyclically heteroskedastic this manifests itself as ripples in the expected cost and service levels nevertheless the cost optimal replenishment policy achieves a constant availability by using time varying safety stocks this is not the case with suboptimal constant safety stock policies where the availability fluctuates over the cycle

a note on price discount based on early order commitment in a single manufacturer multiple retailer supply chain abstract early order commitment eoc is a strategy for supply chain coordination wherein the retailer commits to purchasing from a manufacturer a fixed order quantity a few periods in advance of the regular delivery lead time in this paper we formulate and analyze the eoc strategy for a decentralized two level supply chain consisting of a single manufacturer and multiple retailers who face external demands that follow an autocorrelated ar 1 process over time we characterize the special structure of the optimal solutions for the retailers eoc periods to minimize the total supply chain cost and discuss the impact of demand parameters and cost parameters we then develop and compare three solution approaches to solving the optimal solution using this optimal cost as the benchmark we investigate the effectiveness of using the wholesale price discount scheme for the manufacturer to coordinate this decentralized system we give numerical examples to show the benefits of eoc to the whole supply chain examine the efficiency of the discount scheme in general situation and provide the special conditions when the full coordination is achieved

a semi parametric approach for estimating critical fractiles under autocorrelated demand abstract forecasting critical fractiles of the lead time demand distribution is an important problem for operations managers making newsvendor type inventory decisions in this paper we propose a semi parametric approach to forecasting the critical fractile when demand is serially correlated starting from a user defined but potentially misspecified forecasting model we use historical demand data to generate empirical forecast errors of this model these errors are then used to 1 parametrically correct for any bias in the point forecast conditional on the recent demand history and 2 non parametrically estimate the critical fractile of the demand distribution without imposing distributional assumptions we present conditions under which this semi parametric approach provides a consistent estimate of the critical fractile and evaluate its finite sample properties using simulation and real data for retail inventory planning

balancing retailer inventories this paper examines the optimality of inventory balancing in a one warehouse n retailer distribution system facing stochastic demand for a single product over t successive time intervals in particular we consider the division of predetermined quantities of warehouse stock among retailers in each interval balancing attempts to bring the retailer inventories to the same normalized with respect to first interval demand net inventory level when the demand distribution over the t periods is symmetric with respect to all pairs of retailers and retailer cost over the t intervals is a convex function of the t shipments we show that balancing divisions are optimal the required convexity condition is shown to be satisfied for some familiar cost functions when shortages are backordered and lost however for other cost functions the convexity condition is satisfied under backordering but not under lost sales we also consider the nonidentical retailer demands are not symmetric case and provide examples