benefit incidence with incentive effects measurement errors and latent heterogeneity a case study for china abstract in what is probably the largest cash transfer program in the world today china s dibao program aims to fill all poverty gaps in theory the program creates a poverty trap with 100 benefit withdrawal rate bwr but is that what we see in practice the paper proposes an econometric method of estimating the mean bwr allowing for incentive effects measurement errors and correlated latent heterogeneity under the method s identifying assumptions a feasible instrumental variables estimator corrects for incentive effects and measurement errors and provides a bound for the true value when there is correlated incidence heterogeneity the results suggest that past methods of assessing benefit incidence using either nominal official rates or raw tabulations from survey data are deceptive the actual bwr appears to be much lower than the formal rate and is likely to be too low in the light of the literature on optimal income taxation the paper discusses likely reasons based on qualitative observations from field work the program s local implementation appears to matter far more than incentives implied by its formal rules

note periodic review s s policies for joint replenishment inventory systems this note deals with the joint replenishment problem with stochastic demands a new class of policies called ps s policy is proposed for this problem the proposed policy uses independent periodic review s s policies for each item results on test problems show that the proposed policy is superior to other classes of policies for the problem

perceptions of inevitability and demand for redistribution evidence from a survey experiment abstract believing that inequality is inevitable may limit demand for redistribution we explore this idea with a survey experiment in south africa one of the most unequal countries in the world inevitability beliefs can be influenced by learning about lower inequality elsewhere we find that the demand for redistributive policies reacts to this information while it is insensitive to other types of information messages our analysis suggests a promising and heretofore unexplored avenue of research for refining our understanding of the determinants of demand for redistribution

an efficient algorithm for a generalized joint replenishment problem in most multi item inventory systems the ordering costs consist of a major cost and a minor cost for each item included applying for every individual item a cyclic inventory policy where the cycle length is a multiple of some basic cycle time reduces the major ordering costs an efficient algorithm to determine the optimal policy of this type is discussed in this paper it is shown that this algorithm can be used for deterministic multi item inventory problems with general cost rate functions and possibly service level constraints of which the well known joint replenishment problem is a special case some useful results in determining the optimal control parameters are derived and worked out for piecewise linear cost rate functions numerical results for this case show that the algorithm significantly outperforms other solution methods both in the quality of the solution and in the running time

inventory pooling under heavy tailed demand risk pooling has been studied extensively in the operations management literature as the basic driver behind strategies such as transshipment manufacturing flexibility component commonality and drop shipping this paper explores the benefit of risk pooling in the context of inventory management using the canonical model first studied in eppen eppen gd 1979 effects of centralization on expected costs in a multi location newsboy problem management sci 25 5 498 501 specifically we consider a single period multilocation newsvendor model where n different locations face independent and identically distributed demands and linear holding and backorder costs we show that eppen s celebrated result i e that the expected cost savings from centralized inventory management scale with the square root of the number of locations depends critically on the light tailed nature of the demand uncertainty in particular we establish that the benefit from pooling relative to the decentralized case in term

fiscal redistribution and income inequality in latin america income inequality in latin america ranks among the highest in the world it can be traced back to the unequal distribution of assets especially land and education in the region but the extent to which asset inequality translates into income inequality depends on the redistributive capacity of the state this paper documents the performance of latin american fiscal systems from the perspective of income redistribution using newly available information on the incidence of taxes and transfers across the region the findings indicate that i the differences in income inequality before taxes and transfers between latin america and western europe are much more modest than those after taxes and transfers ii the key reason is that in contrast with industrial countries in most latin american countries the fiscal system is of little help in reducing income inequality and iii in countries where fiscal redistribution is significant it is achieved mostly through transfers rather than taxes these facts stress the need for fiscal reforms across the region to further the goal of social equity however different countries need to place different relative emphasis on raising tax collection restructuring the tax system and improving the targeting of expenditures

optimizing reorder intervals for two echelon distribution systems with stochastic demand we consider a periodic review inventory system in which n non identical retailers replenish from a warehouse which further replenishes from an outside vendor with ample supply each facility faces poisson demand and replenishes according to a base stock policy in a fixed time interval fixed costs are incurred for placing an order the warehouse fills the retailers orders in the same sequence as the occurrence of the demand at the retailers the objective is to minimize the average system cost per period this paper develops an evaluation scheme and provides a method to obtain the optimal base stock levels and reorder intervals specifically with fixed reorder intervals we show that the optimal base stock levels can be obtained by generalizing the result in the literature to find the optimal reorder intervals we first allocate the total system cost to each facility and then construct a lower bound to the allocated facility cost these lower bound functions which are separable functions of reorder i

income distribution political instability and investment abstract this paper successfully tests on a sample of 71 countries for the period 1960 85 the following hypotheses income inequality by fuelling social discontent increases sociopolitical instability the latter by creating uncertainty in the politico economic environment reduces investment as a consequence income inequality and investment are inversely related since investment is a primary engine of growth this paper identifies a channel for an inverse relationship between income inequality and growth we measure socio political instability with indices which capture the occurrence of more or less violent phenomena of political unrest and we test our hypotheses by estimating a two equation model in which the endogenous variables are investment and an index of socio political instability our results are robust to sensitivity analysis on the specification of the model and the measure of political instability and are unchanged when the model is estimated using robust regression techniques

coordinated replenishments in inventory systems with correlated demands abstract demand correlation among different inventory items is common in real life multi item inventory systems however this phenomenon has not received sufficient attention in the existing inventory literature in this paper we construct a markovian model for a two item inventory system with correlated demands and coordinated replenishments we obtain an expression for the long run total cost per unit of time under the can order replenishment policy for the scenario with independent replenishments the explicit formula for the long run total cost per time unit can be derived which leads to analytical solutions for the optimal policies we then present numerical examples of the optimal can order policies and discuss some managerial insights regarding demand correlation and replenishment coordination our numerical results also suggest a possible heuristic method for obtaining can order replenishment policies for multi item systems

measuring poverty in a growing world or measuring growth in a poor world the extent to which growth reduces global poverty has been disputed for 30 years although there are better data than ever before controversies are not resolved a major problem is that consumption measured from household surveys which is used to measure poverty grows less rapidly than consumption measured in national accounts in the world as a whole and in large countries particularly india china and the united states in consequence measured poverty has fallen less rapidly than appears warranted by measured growth in poor countries one plausible cause is that richer households are less likely to participate in surveys but growth in the national accounts is also upward biased and consumption in the national accounts contains large and rapidly growing items that are not consumed by the poor and not included in surveys so it is possible for consumption of the poor to grow less rapidly than national consumption without any increase in measured inequality current statistical procedures in poor

deterministic eoq with partial backordering and correlated demand caused by cross selling abstract there has been much work regarding the deterministic eoq with partial backordering the majority of these studies assume no correlation in sales so independent demands across items is applied in the models however it is generally recognized that cross selling effects between items often appear in real contexts thus incorporating such effects in the inventory model in the form of correlated demands makes it of more practical relevance in this paper the authors address a two item inventory system where the demand of a minor item is correlated to that of a major item because of cross selling we firstly present a two item eoq model with identical order cycles where the unmet demand of the major item can be partially backordered with lost sales whereas the demand of the minor item must be met without stockouts this model is further extended to fit a more practical case where the order cycle of the major item is an integer multiple of that of the minor item the optimal solutions of the two models as well as the inventory decision procedures are also developed comparative analysis on these two eoq models has been drawn in the computational study which presents some insights into the parameter effect on the optimal inventory policy

the economic lives of the poor in what turned out to be a rhetorical master move the 1990 world development report from the world bank defined the extremely poor people of the world as those who are currently living on no more than 1 per day per person measured at the 1985 purchasing power parity ppp exchange rate in 1993 the poverty line was updated to 1 08 per person per day at the 1993 ppp exchange rate which is the line we use in this paper poverty lines have always existed indeed 1 per day was chosen in part because of its proximity to the poverty lines used by many poor countries 1 however the 1 a day poverty line has come to dominate the conversations about poverty to a remarkable extent

social mobility and redistributive politics just like economists voters have conflicting views about redistributive taxation because they estimate its incentive costs differently we model rational agents as trying to learn from their dynastic income mobility experience the relative importance of effort and predetermined factors in the generation of income inequality and therefore the magnitude of these incentive costs in the long run left wing dynasties believing less in individual effort and voting for more redistribution coexist with right wing dynasties this allows us to explain why individual mobility experience and not only current income matters for political attiitudes and how persistent differences in perceptions about social mobility can generate persistent differences in redistribution across countries

school choice stratification and information on school performance lessons from chile in the early 1980s chile implemented a nationwide school choice system under which the government finances education via a flat per student sub sidy or voucher to the public or private school chosen by a family at present about 94 percent of all schools public religious and secular private are voucher funded more than half of urban schools are private and most of these operate as for profit institutions 1 since the early 1990s chile has also publicized information on school performance and increased per pupil expen diture substantially despite these and other reforms chile has found it challenging to improve students learning outcomes 2 hsieh and urquiola find that the country s rel ative performance in international tests did not change much between 1970 and 1999 3 its performance on the 2000 programme for international student assessment pisa is not only much lower than the oecd average but is similar to that of other latin american countries and low relative to countries with similar income per capita

crises and the poor socially responsible macroeconomics this paper presents evidence on the impact of economic crisis on poverty and inequality in latin america crises not only result in higher poverty rates but also may cause irreversible damage to the human capital of the poor in light of this evidence the author concludes that crisis avoidance and a pro poor response to crisis should be a major component of a poverty reduction strategy as a result the paper analyses the role of exchange rate policy capital controls and countercyclical fiscal policy in generating or avoiding crisis responses to macroeconomic crisis are assessed by considering the effects of different policy combinations the use of safety nets and the composition of fiscal adjustment to protect the income of the poor in the face of macroeconomic adjustment the main lesson is that socially responsible macroeconomic policy can protect the poor during times of crisis and simultaneously contribute to lower chronic poverty

alternative definitions of headship and the feminisation of income poverty in post apartheid south africa abstract in measuring gender differences in the risk of income poverty many studies use female headship as a proxy for gender however a number of well documented concerns with the use of self reported headship as an analytical category have suggested that headship is often a relatively blunt unit of analysis against the backdrop of a large and growing difference in income poverty rates between self reported female and male headed households in post apartheid south africa this study considers several alternative definitions of headship that have been proposed in the development literature the findings suggest that there is an association between self reported female headship and a female household member being identified as the main breadwinner however the conventional definition of headship is likely to underestimate the growing risk of income poverty in female headed households relative to male headed households compared with several alternative definitions the findings also suggest that alte

a multi item periodic replenishment policy with full truckloads abstract in this paper we consider a stochastic multi item inventory problem a retailer sells multiple products with stochastic demand and is replenished periodically from a supplier with ample stock at each order instant it is decided which product to order and how much to order for the delivery of the products trucks with a finite capacity are available the dispatched trucks arrive at the retailer after a constant leadtime and with each truck fixed shipping costs are charged independent on the number of units shipped additionally linear holding and backorder costs at the end of a review period are considered since fixed transportation costs are high coordination of orders and full truckload shipments can benefit from economies of scale we propose a dynamic order up to policy where initial ordersizes can be reduced as well as enlarged to create full truckloads we show how to compute the policy parameters and in a detailed numerical study we compare our policy with a lower bound and an uncoordinated periodic replenishment policy an excellent cost performance of the proposed policy can be observed when average time between two shipments is not too large and fixed shipping costs are high

the future of the income tax the federal income tax has been under attack by the economics profession for more than a decade the attack comes from two directions supply siders who believe that progressive income taxation impairs economic incentives and more traditional economists who would substitute a progressive expenditure tax for the income tax 2 at one time support for the expenditure tax was confined to a few members of our profession including such distinguished names as john stuart mill irving fisher nicholas kaldor and james meade today it is fair to say that many if not most economists favor the expenditure tax or a flat rate income tax this group has joined the opponents of progressive taxation in the attack on the income tax despite an incessant barrage from both groups no country in the world is planning to abandon the income tax or is even considering a personal expenditure tax a wave of tax reform beginning with the u s reform in 1986 has been sweeping the world aimed at improving the income tax not at eliminating it tax preferences formerly regarded as sacrosanct are being removed and there is a distinct movement toward comprehensive income taxation 3 however individual income tax rates are being cut tax progressivity has been declining almost everywhere and reliance on the income tax has been diminishing it will come as no surprise to this audience that i approve of the base broadening feature of the current tax reform movement but i believe that the reduction in the redistributive effect of the income tax has gone too far in this paper i shall show that the progressivity of the u s tax system never very pronounced except during and immediately after the two world wars has been declining for more than two decades and that the tax reform act of 1986 reversed this decline but only slightly consequently we have a long way to go to improve the equity of the tax system i believe this can be done without punitive tax rates that will hurt economic incentives i begin with a brief review of recent changes in the u s distribution of income and follow this with an analysis of the effect of taxes on the income distribution i next examine arguments for and against the income tax with particular emphasis on its effects on economic incentives and its merits when compared with the expenditure tax i then evaluate the income tax as it emerged from the 1986 tax reform and conclude with tjoseph pechman passed away on august 19 1989 his presidential address was delivered at the onehundred second meeting of the american economic association december 29 1989 atlanta georgia joseph a pechman economic studies program the brookings institution 1775 massachusetts avenue nw washington dc 20036 i have benefited from the comments and suggestions on an earlier draft of this paper by henry j aaron richard goode jane g gravelle robert w hartman donald w kiefer herbert e klarman robert d reischauer clifford m winston and h peyton young but they should not be held responsible for the views expressed in this paper i am indebted to richard kasten for various simulations i am also grateful to stephen j kastenberg for research assistance and to diane a shugart valerie m owens and sara c hufham for secretarial assistance some of the more extreme supply siders argued that large tax cuts pay for themselves see for example laffer 1981 but i believe it is fair to say that this view has been totally discredited for a more reasonable supply side view see the economic report of the president 1982 2see for example michael j boskin 1978 david e bradford 1980 charles l ballard don fullerton john shoven and john whalley 1985 paul courant and edward gramlich 1982 martin feldstein 1978 robert hall and alvin rabushka 1985 john kay and mervyn king 1983 charles mclure 1987 mieszkowski 1980 and lawrence summers 1981 it is interesting that the recent popularity of the expenditure tax among economists was stimulated by a tax lawyer william d andrews 1974 3see pechman 1988

the poverty and heterogeneity among female headed households revisited the case of panama abstract investigating whether female headed households fhhs are particularly disadvantaged requires more systematic means of comparing poverty than are typically found in past studies in panama while fhhs as a whole appear to be better off on average such results are somewhat sensitive to assumptions about economies of scale in household consumption more disaggregated analysis reveals that particular segments of fhhs particularly self reported fhhs with common law partners living in urban areas are disadvantaged in both consumption and some nonconsumption dimensions thus less systematic analysis could fail to identify such pockets of poverty that might deserve special policy attention

a heuristic joint replinishment policy for the case of heterogeneity among items abstract the q s s policy is considered among the best for solving the well known stochastic joint replenishment problem however it has some shortcomings if much heterogeneity exists among the items consequently a new heuristic control policy is constructed the cornerstone is a policy iteration improvement step assuming a single possibility for making a joint order and thus to deviate from the rule that the items are governed by independent re order and order up to s s policies but this policy iteration improvement step is done repeatedly at each demand epoch it is only required the development of one dimensional value functions of state variables in order to accomplish the policy iteration improvement step knowledge about good order up to values is important furthermore a relaxation parameter is introduced such that one can make it easier or more difficult to issue a joint order when following the policy iteration improvement step finally in case a joint order is made a vector of can order points is used to include additional items the policy is denoted a c s policy numerical results shows that the new policy performs significantly better than the q s s policy for cases with heterogeneity among items furthermore from a given optimal can order policy one can construct a better c s policy

latin america s social policy challenge education social insurance redistribution abstract long regarded as a region beset by macroeconomic instability high inflation and excessive poverty and inequality latin america has undergone a major transformation over the last 20 years the region has seen improved macroeconomic management and substantial and sustained reductions in poverty and inequality in this paper we argue that social policy including human capital and education social insurance and redistribution need special attention if achievements of the last two decades are to be sustained and amplified starting in the mid 1990s many governments in the region introduced a variety of programs including noncontributory pensions and health insurance and cash transfers targeted to the poor social spending in latin america increased sharply these policies have been widely praised and we believe they have resulted in substantial improvements in the lives of the poor in the region however a more nuanced view shows some worrisome trends moving forward we believe it is nec

periodic versus can order policies for coordinated multi item inventory systems the coordinated multi item inventory problem refers to the problem of managing inventories where there is a joint fixed cost for replenishing plus an item by item fixed cost for each item included in the replenishment order given that the optimal solution is likely to be too complex attention has focused on fixed heuristics and in particular can order or s c s policies this paper makes two contributions first a new lower bound on the cost of the optimal policy is proposed in order that the performance of heuristics may be measured second motivated by the lower bound a simple periodic policy is proposed and shown to be an improvement over can order policies for many data sets

does aid affect inequality we show that there was a negative correlation between pro poor aid and inequality in the period before the mid 2000s this article provides an explanation for this observed relationship using pane

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

how does gender affect the adoption of agricultural innovations why do men and women adopt agricultural technologies at different rates evidence from ghana suggests that gender linked differences in the adoption of modern maize varieties and chemical fertilizer result from gender linked differences in access to complementary inputs this finding has important policy implications because it suggests that ensuring more widespread and equitable adoption of improved technologies may not require changes in the research system but rather introduction of measures that ensure better access for women to complementary inputs especially land labor and extension services

a dynamic joint replenishment policy with auto correlated demand we consider a joint replenishment problem where the product demands are auto correlated but independent of each other a dynamic periodic review policy is developed and its parameters are determined by a heuristic which aims at minimizing the total inventory cost which includes the holding cost the set up cost and the shortage cost the heuristic updates the review interval and the target inventory level of every product at each review point based on the current inventory status and the past demand data a simulation model is developed to compare the performance of this proposed policy with an existing periodic review policy the results show that the proposed policy has consistently achieved significant saving in all the different experimental scenarios

household food security and child nutrition the interaction of income and gender of household head abstract data from kenya and malawi suggest that food security and preschooler nutritional status are influenced by the interaction of income and gender of the head of household rather than simply one or the other not only is household food security influenced by total household income but the proportion of income controlled by women has a positive and significant influence on household caloric intake households were disaggregated not simply in male and female headed households but female headed households were further disaggregated into de jure legal head of household is a woman and de facto female headed households male head of household is absent more than 50 of the time in both kenya and malawi the de facto female headed households had the lowest income despite this low income preschoolers nutritional status was significantly better than in the higher income male headed and de jure female headed households the ability to improve nutritional status in a low income environment in the de facto female headed households is related to a combination of child feeding practices and other nurturing behavior the findings suggest that interventions that exploit incentives to invest in children can provide more immediate improvements in child health and nutrition where sustained income growth is possible only in the long term

history lessons institutions factor endowments and paths of development in the new world the explanations offered for the contrasting records of long run growth and development among the societies of north and south america most often focus on institutions the traditional explanations for the sources of these differences in institutions typically highlight the significance of national heritage or religion we in contrast argue that a hemispheric perspective across the wide range of colonies established in the new world by the europeans suggests that although there were many influences factor endowments or initial conditions had profound and enduring effects on the long run paths of institutional and economic development followed by the respective economies

taxes and income distribution in chile some unpleasant redistributive arithmetic abstract this paper quantifies the direct impact of taxes on income distribution at the household level in chile and estimates the distributional effect of several changes in the tax structure we find that income distributions before and after taxes are very similar gini coefficients of 0 488 and 0 496 respectively moreover radical modifications of the tax structure such as raising the value added tax from 18 to 25 or substituting a 20 flat tax for the present progressive income tax affect the after tax distribution only slightly we present some arithmetic showing that the scope for direct income redistribution through progressivity of the tax system is rather limited by contrast for parameter values observed in chile and possibly in most developing countries the targeting of expenditures and the level of the average tax rate are far more important determinants of income distribution after government transfers thus a high yield proportional tax can have a far bigger equalizing impact than a low yield progressive tax moreover a simple model shows that the optimal tax system is biased against progressive taxes and towards proportional taxes with a bias that grows with the degree of inequality of pre tax incomes our results suggest that to reduce income inequality the focus of discussion should be on the amount to be redistributed the targeting of public spending and the relative efficiency of alternative taxes and not on the progressivity of the tax system

the implications of female household headship for food consumption and nutritional status in the dominican republic abstract female control of household resources is often associated with consumption preferences which favor basic needs and child welfare using data from the dominican republic this study tests differences in spending patterns consumption preferences and child nutritional anthropometric status according to four definitions of female household headship female headed households fhh allocate the same amount or less of their budgets to food than male headed households mhh in absolute and proportional terms fhh consume higher quality more expensive and protein dense foods more animal products less of beans and rice than mhh average caloric adequacy per adult equivalent is equal or lower in fhh but children s anthropometric status is the same or higher it is significantly higher in low income fhh possibly due to intrahousehold allocation of food which favors children

coordinated replenishments in a multi item inventory system with compound poisson demands in many practical applications or multi item inventory systems significant economies of scale can be exploited when coordinating replenishment orders for groups of items this paper considers a continuous review multi item inventory system with compound poisson demand processes excess demands are backlogged and each replenishment requires a lead time there is a major setup cost associated with any replenishment of the family of items and a minor item dependent setup cost when including a particular item in this replenishment moreover there are holding and penalty costs we present an algorithm which searches for a simple coordinated control rule minimizing the long run average cost per unit time subject to a service level constraint per item on the fraction of demand satisfied directly from on hand inventory this algorithm is based on a heuristic decomposition procedure and a specialized policy iteration method to solve the single item subproblems generated by the decomposition procedure the model applies to multi location inventory systems with similar cost structures for coordinated deliveries

revenue management through dynamic cross selling in e commerce retailing we consider the problem of dynamically cross selling products e g books or services e g travel reservations in the e commerce setting in particular we look at a company that faces a stream of stochastic customer arrivals and may offer each customer a choice between the requested product and a package containing the requested product as well as another product what we call a packaging complement given consumer preferences and product inventories we analyze two issues 1 how to select packaging complements and 2 how to price product packages to maximize profits we formulate the cross selling problem as a stochastic dynamic program blended with combinatorial optimization we demonstrate the state dependent and dynamic nature of the optimal package selection problem and derive the structural properties of the dynamic pricing problem in particular we focus on two practical business settings with the emergency replenishment model and without the lost sales model the possibility of inventory replenishment in the case of a product stockout for the emergency replenishment model we establish that the problem is separable in the initial inventory of all products and hence the dimensionality of the dynamic program can be significantly reduced for both models we suggest several packaging pricing heuristics and test their effectiveness numerically

the 2bin system for controlling medical supplies at point of use abstract the increase in cost of supplies and services is outpacing the increase in revenues at many hospitals to address this cost increase hospitals are seeking more efficient ways to store and manage vast inventories of medical supplies a parsimonious and efficient inventory system which we call 2bin is becoming increasingly popular in north american hospitals under the 2bin system inventory is stored in two equal sized bins 2bin systems are reviewed periodically and empty bins are replenished in recent years the adoption of rfid technology for 2bin systems is allowing continuous time tracking of empty bins increasing inventory visibility in this paper we model the 2bin inventory system under periodic and continuous review for periodic review we show that the long run average cost per unit time is quasi convex enabling a simple search for the optimal review cycle for continuous review we present a semi markov decision model characterize the optimal replenishment policy and provide a solution approach to obtain the long run average cost per unit time using data obtained from hospitals currently using rfid enabled 2bin systems we estimate the economic benefits of using the best periodic review length i e parameter optimization and of using a continuous review inventory policy i e policy improvement we characterize system conditions such as the number of medical supplies used replenishment costs stock out costs etc that favor each option and provide insights to hospital management on system design considerations that favor the use of periodic or continuous review

business organisations party systems and tax composition in developing countries a comparison between colombia and peru abstractthis paper explores the relationship between socio political institutions and tax composition in developing countries it argues that strong business organisations and stable political party systems reduce the uncertainty of fiscal contracts for economic elites the decrease in uncertainty leads elites to accept a larger share of the tax burden which governments then collect using progressive tax types more intensively to illustrate this claim i provide evidence from a comparative analysis of the peruvian and the colombian tax history between 1970 and 2010

computing the optimal replenishment policy for inventory systems with random discount opportunities the paper considers the optimal control of a single item continuous review inventory system with random demand and discount opportunities items can always be purchased with the regular order setup and variable costs however when a discount opportunity occurs they can also be purchased with a different setup cost and a lower variable cost demands for individual items and discount opportunities occur according to independent poisson processes the paper proposes an algorithm to compute the parameters of the optimal replenishment policy which has been shown to be an r r d d policy wherer

where do the poor live this paper argues that the distribution of global poverty has changed and that most of the world s poor no longer live in countries officially classified as low income countries lics it is estimated that the majority of the world s poor or up to a billion people live in middle income countries mics this pattern is largely as a result of the recent graduation into the mic category of a number of populous countries the paper discusses the trends in the distribution of global poverty and opens a wider discussion on the potential implications for aid and development cooperation

coordinated replenishment strategies in inventory distribution systems in this paper we study the impact of coordinated replenishment and shipment in inventory distribution systems we analyze a system with multiple retailers and one outside supplier random demand occurs at each retailer and the supplier replenishes all the retailers in traditional inventory models each retailer orders directly from the supplier whenever the need arises we present a new centralized ordering policy that orders for all retailers simultaneously the new policy is equivalent to the introduction of a warehouse with no inventory that is in charge of the ordering allocation and distribution of inventory to the retailers under such a policy orders for some retailers may be postponed or expedited so that they can be batched with other retailers orders which results in savings in ordering and shipping costs in addition to the policy we propose for supplying inventory to the retailers we also consider three other policies that are based on these well known policies in the literature a can order policy b echelon inventory policy and c fixed replenishment interval policy furthermore we create a framework for simultaneously making inventory and transportation decisions by incorporating the transportation costs or limited truck capacities we numerically compare the performance of our proposed policy with these policies to identify the settings in which each policy would perform well

an association clustering algorithm for can order policies in the joint replenishment problem abstract many studies have shown that the total cost of employing joint replenishment for correlated items is less than the total cost of using single item replenishment savings increase dramatically when the demand between items is closely related although the benefits of joint replenishment are significant it is difficult to define the demand correlation among items especially when the number of items increases a large number of items reduces the efficiency and advantage of the multi item inventory control to overcome this difficulty an association clustering algorithm this paper proposes to evaluate the correlated demands among items the proposed algorithm utilizes the support concept in association rule analysis to measure the similarity among items based on these measurements a clustering method is developed to group items with close demand in a hierarchal way the can order policy is then applied to the optimal clustering result as decided by the proposed performance index to illustrate the benefits of the proposed association clustering algorithm for replenishment systems a set of simulations and a sensitivity analysis is conducted the results of the experiments show that the proposed method outperforms several replenishment models

the multiple family elsp with safety stocks the multiple family economic lot scheduling problem with safety stocks mfelsp ss with normally distributed time stationary demand is considered in a manufacturing setting where the relevant costs include family setup costs item setup costs and inventory holding costs for both cycle and safety stocks a family is a subset of the items that share a common family setup with its associated setup cost and setup time each item within the family may have its own setup time and setup cost the families form a partition of the set of items manufactured on a single facility the safety stock level for any item is a function of the time interval between production runs for the item the service level specified and the variance of its demand we consider safety stocks explicitly in the formulation as their holding costs vary nontrivially with the models decision variables the mfelsp ss differs from multilevel inventory models with family setups in that the former assumes noninstantaneous inventory replenishment and considers the cost of holding safety stocks the latter assumes instantaneous replenishment and does not directly assess the impact of safety stock levels on the total cost an efficient solution procedure is developed for this model properties of the nonconvex feasible space are identified and used in the solution approach the solution to the mathematical model comprises the basic period length the family multipliers and the item multipliers that give the lowest total cost of setups and carrying inventory the family multipliers and item multipliers are restricted to integer powers of two

the strugglers the new poor in latin america summary we identify a group of people in latin america that are not poor but not middle class either namely strugglers in households with daily income per capita between 4 and 10 at constant 2005 ppp this group will account for about a third of the region s population over the next decades as the size and income of the middle class rises they could become increasingly marginalized the cash transfers they receive are largely offset by indirect taxes the benefit of schooling and other in kind transfers they receive is questionable after adjusting for quality we discuss implications for the social contract

a paradox of redistribution in international aid the determinants of poverty oriented development assistance summary donors differ in the amount of official development assistance dedicated to poverty reduction we investigate the causes of variation over time and donors by employing both a regression approach with aggregate data on bilateral aid and two short country studies on germany and the united kingdom we find that there is a trade off between the total amount of money given and the amount of money given to poor countries the trade off is similar to the paradox of redistribution of targeting vs redistribution in rich welfare states case study evidence illustrates how countries have managed this tradeoff

what is middle class about the middle classes around the world we expect a lot from the middle classes jim frederick writing in time magazine in 2002 stated china s burgeoning middle class holds the key to the future of the country in a more academic vein easterly 2001 concludes based on a comparison of a large number of countries that countries that have a larger middle class tend to grow faster at least if they are not too ethnically diverse in another article birdsall graham and pettinato 2000 rue the shrinking of the middle class the backbone of both the market economy and of democracy in most advanced societies in the face of burgeoning globalization the economic historian david landes writing about the wealth and poverty of nations 1998 explains england s early ascendancy in terms of the great english middle class of the eighteenth and nineteenth centuries of course there is nothing new about this faith in the middle class it follows a long line of theorizing going back at least to max weber 1905 at least three distinct arguments are traditionally made in one new entrepreneurs armed with a capacity and a tolerance for delayed gratification emerge from the middle class and create employment and productivity growth for the rest of society for a formalization of this argument see acemoglu and zilibotti 1997 in a second perhaps more conventional view the middle class is primarily a source of vital inputs for the entrepreneurial class it is their middle class values their emphasis on the accumulation of human capital and savings that makes them central to the process of capitalist accumulation for example doepke and zilibotti 2005 2007 the third view a staple of the business press emphasizes the middle class consumer the consumer who is willing to pay a little extra for quality in this view the middle class demand for quality consumer goods feeds investment in production and marketing which in turn raises income levels for everyone murphy shleifer and vishny 1989 1 this essay asks what we should make of these arguments in the context of today s developing countries starting from data on patterns of consumption and investment by the middle class we look for what is distinct about the global middle class especially when compared to the global poor defined as those whose per capita daily consumption valued at purchasing power parity exchange rates is below 2 a day who were the subject of a previous essay in this journal banerjee and duflo 2007b in particular is there anything special about the way the middle class spend their money earn their incomes or bring up their children

redistribution under the right in latin america electoral competition and organized actors in policymaking unexpected social policy expansion and progressive tax reforms initiated by right wing governments in latin america highlight the need for further theory development on the politics of redistributi

dollar a day revisited the article presents the first major update of the international 1 a day poverty line proposed in world development report 1990 poverty for measuring absolute poverty by the standards of the world s poorest countries in a new and more representative data set of national poverty lines a marked economic gradient emerges only when consumption per person is above about 2 00 a day at 2005 purchasing power parity below this the average poverty line is 1 25 which is proposed as the new international poverty line the article tests the robustness of this line to alternative estimation methods and explains how it differs from the old 1 a day line

optimal control policy for stochastic inventory systems with markovian discount opportunities in this paper we study a single item continuous review inventory system with poisson demand in addition to the standard cost structure of a fixed setup cost and a quasiconvex expected inventory holding and shortage cost special opportunities for placing orders at a discounted setup cost occur according to a poisson process that is independent of the demand process this model has been studied as a subproblem of multi item location inventory systems where there are economies of scale in joint replenishment for the single item model the literature proposes the s c s policy under which an order is placed to increase the inventory position to s either when the inventory position drops to s or when the inventory position is at or below c and a discount opportunity occurs we prove that the s c s policy is optimal for the model develop an efficient algorithm for computing optimal control parameters s c s and carry out a parametric analysis showing the effects of changes in problem paramete

does government spending affect income inequality a meta regression analysis in this paper findings of a meta regression analysis are presented exploring the effects of government spending on income inequality with a particular focus on low and middle income countries we identify a total of 84 separate studies containing over 900 estimates of the effect of one or more measures of spending on one or more measures of income inequality the results show some evidence of a moderate negative relationship between government spending and income inequality which is strongest for social welfare and other social spending and when using the gini coefficient or the top income share as the measure of inequality however both the size and direction of the estimated relationship between government spending and income inequality is affected by a range of other factors including the control variables and estimation method used we also find evidence of publication bias in that negative estimates of the relationship appear to be under reported in the literature

alternative definitions of female headship in the dominican republic abstract different definitions of female household headship have different implications for the economic status and welfare of members of female headed households fhh using data from the dominican republic this study compares four definitions of fhh self definition no adult males 18 60 present female earns over 50 of earned or of total income the definitions are associated but each defines a different group half of self defined fhh contain adult males half of those in which the woman is the major earner are self defined fhh in the dominican republic female headship by any definition is not associated with lower income per capita but sources of income are quite different fhh are more dependent on transfers and gifts than wages fhh defined by earnings are of higher income on average demographic composition of fhh is significantly different from male headed households mhh

does government spending affect income poverty a meta regression analysis summary this paper presents the results of a meta regression analysis of the relationship between government spending and income poverty with a focus on low and middle income countries through a comprehensive search and screening process we identify a total of 19 cross country econometric studies containing 169 estimates of this relationship we find that the size and direction of the estimated relationship are affected by a range of factors most notably the composition of the sample used for estimation the control variables included in the regression model and the type of government spending overall we find no clear evidence that higher government spending has played a significant role in reducing income poverty in low and middle income countries this is consistent with the view that fiscal policy plays a much more limited redistributive role in developing countries in comparison with oecd countries in addition we find that the relationship between government spending and poverty is on average less negative for countries in sub saharan africa and more negative for countries in eastern europe and central asia compared to other regions we also find that the relationship is less negative for government consumption spending in comparison with other sectors finally we find some evidence indicating the possibility of publication bias

calculating can order policies for the joint replenishment problem by the compensation approach abstract in this paper we consider the stochastic joint replenishment problem we coordinate the replenishment of an inventory with several items where the fixed cost of a replenishment consists of a major order cost for each order and a minor order cost for each item participating in the order the literature has focused on two kinds of policies can order policies and periodic replenishment policies generally speaking the can order policy performs better when the major ordering cost is relatively low and the periodic replenishment policies better when the major ordering cost is relatively high we present a new method for calculating can order policies which dominates existing methods on examples where the can order policy performs better than the periodic replenishment policies the method is based on a compensation approach where an item placing an order receives a compensation from other items benefitting from the order opportunity

the stochastic economic lot scheduling problem cyclical base stock policies with idle times in this paper we discuss stochastic economic lot scheduling problems elsp i e settings where several items need to be produced in a common facility with limited capacity under significant uncertainty regarding demands production times setup times or combinations thereof we propose a class of production inventory strategies for stochastic elsps and describe how a strategy which minimizes holding backlogging and setup costs within this class can be effectively determined and evaluated the proposed class of strategies is simple but rich and effective when the facility is assigned to a given item production continues until either a specific target inventory level is reached or a specific production batch has been completed the different items are produced in a given sequence or rotation cycle possibly with idle times inserted between the completion of an item s production batch and the setup for the next item an optimal strategy within the class can be determined and all relevant performance measures can be evaluated in just a few cpu seconds using a 486 based pc we also derive a number of easily computable lower bounds for the optimal cost value and establish a comparison with deterministic elsps

an approach to evaluate the impact of interaction between demand forecasting method and stock control policy on the inventory system performances abstract usually in stock control studies demand data are considered as an input to the model without explicitly considering that they are the results of a demand forecasting system stock control system is examined independently of the demand forecasting system and it is assumed that demand data or forecast errors have been properly modelled however the interactions that may exist between demand forecasting methods and stock control systems in terms of their effects on global system performances are not considered in the paper an approach for evaluating these interactions based on a comparative simulation test of global system costs using historical data is presented the approach is explained through a real case the replenishment from different suppliers of a central depot of tinned food which supplies more than 700 items to warehouses at the lower echelon results of the simulation study show that traditional measures of forecast errors cannot be taken as sole indicators for the choice among different demand forecasting methods these methods on the contrary have to be evaluated on the basis of total costs and service level of the global inventory control system

distributive politics and economic growth a crude distinction between economics and politics would be that economics is concerned with expanding the pie while politics is about distributing it in this paper we analyze the relationship between the two we focus on how an economy s initial configuration of resources shapes the political struggle for income and wealth distribution and how that in turn affects long run growth our main conclusion is that inequality is conducive to the adoption of growth retarding policies we derive this result from a simple political economy model of growth and present cross country evidence consistent with it the key feature of our model is that individuals differ in their relative factor endowments we distinguish between two types of factors an accumulated factor called capital and a nonaccumulated factor called labor growth is driven by the expansion of the capital stock which is in turn determined by individual saving decisions long run growth is endogenous as the aggregate production function is taken to be linearly homogeneous in capital and productive government services taken together the provision of government services is financed by a tax on capital because government services are productive a small tax on

effects of correlation on intermittent demand forecasting and stock control abstract this study investigates the effects of three different types of correlation on forecasting and stock control of intermittent demand items applying appropriate forecasting and stock control methods to theoretically generated compound poisson demand data we show that correlation in intermittent demand does play a role in forecast quality and stock control performance negative autocorrelation levels lead to higher service levels than positive values while cost does not significantly change our results also show that high intermittency levels intensify these changes in service level we also show that cross correlation produces results in the opposite direction of autocorrelation in size or intervals that is positive negative cross correlation leads to higher lower service levels

working women in an urban setting traders vendors and food security in accra abstract data collected from a 1997 household survey carried out in accra ghana are used to look at the crucial role that women play as income earners and securing access to food in urban areas one third of the households surveyed are headed by women for all households women s labor force participation is high with 75 of all households having at least one working woman the high number of female headed households and the large percentage of working women in the sample provide a good backdrop for looking at how women earn and spend income differently than men in an urban area livelihood strategies for both men and women are predominantly labor based and dependent on social networks for all households in the sample food is still the single most important item in the total budget yet important and striking differences between men s and women s livelihoods and expenditure patterns exist compared to men women are less likely to be employed as wage earners and more likely to work as street food vendors or petty traders women earn lower incomes but tend to allocate more of their budget to basic goods for themselves and their children while men spend more on entertainment for themselves only despite lower incomes and additional demands on their time as housewives and mothers female headed households petty traders and street food vendors have the largest percentage of food secure households women may be achieving household food security but at what cost this paper explores differences in income expenditure and consumption patterns in an effort to answer this question and suggests ways that urban planners and policy makers can address special concerns to working women in urban areas

how does gender affect the adoption of agricultural innovations the case of improved maize technology in ghana why do men and women adopt agricultural technologies at different rates evidence from ghana suggests that gender linked differences in the adoption of modern maize varieties and chemical fertilizer result from gender linked differences in access to complementary inputs this finding has important policy implications because it suggests that ensuring more widespread and equitable adoption of improved technologies may not require changes in the research system but rather introduction of measures that ensure better access for women to complementary inputs especially land labor and extension services

cooperation and game theoretic cost allocation in stochastic inventory models with continuous review we study cooperation strategies for companies that continuously review their inventories and face poisson demand our main goal is to analyze stable cost allocations of the joint costs these are such that any group of companies has lower costs than the individual companies if such allocations exist they provide an incentive for the companies to cooperate we consider two natural cooperation strategies i the companies jointly place an order for replenishment if their joint inventory position reaches a certain reorder level and ii the companies reorder as soon as one of them reaches its reorder level numerical experiments for two companies show that the second strategy has the lowest joint costs under this strategy the game theoretical shapley value and the distribution rule a cost allocation in which the companies share the procurement cost and each pays its own holding cost are shown to be stable cost allocations these results also hold for situations with three companies

a coordinated multi item inventory system for perishables with random lifetime abstract this paper considers the continuous review can order s c s policy for coordinating the replenishment of multiple perishable items with random lifetimes for zero lead time we model this inventory system as a markov process an iterative procedure is proposed to solve the joint replenishment problem for perishable items under positive lead time we investigate the impact of perishability and cost parameters on the performance of the can order policy and compare it to the optimal periodic review s s policy

relationships between corruption political orientation and income inequality evidence from latin america abstractthis research sheds light on the analysis of the impact of corruption and political orientation on income distribution in latin america although it has been theoretically demonstrated that corruption worsens the income distribution the empirical evidence has yielded ambiguous results based on biased estimates not considering a measurement error in the estimation of inequality this article fills this gap by correcting the previous measurement error bias in the fixed effects estimation additionally political orientation and its relationship with income inequality are also investigated the sample covers 18 latin american countries between 1996 and 2012 results reveal that corruption increases income inequality