taxing food and beverages theory evidence and policy we developed a theoretical framework to examine the effect of a change in sales or excise tax on food and beverage demand after considering that consumers may have imperfect tax knowledge are sometimes inattentive to sales tax may not be informed of a sales tax change and pay no sales tax on eligible food or beverages if using food stamps we conducted simulations to assess how much the sales tax elasticity of demand should be adjusted downward from the price elasticity of demand and quantified the advantage of using an excise tax as an anti obesity policy copyright 2013 oxford university press

demand elasticities for food products in brazil a two stage budgeting system the object of this article is to estimate demand elasticities for a basket of staple food important for providing the caloric needs of brazilian households these elasticities are useful in the measurement of the impact of structural reforms on poverty a two stage demand system was constructed based on data from household expenditure surveys pof produced by ibge the brazilian bureau of statistics in 1987 88 and 1995 96 we have used panel data to estimate the model and have calculated income own price and cross price elasticities for eight groups of goods and services and in the second stage for 11 sub groups of staple food products we estimated those elasticities for the whole sample of consumers and for two income groups

fertilizing growth agricultural inputs and their effects in economic development this paper estimates the role of agronomic inputs in cereal yield improvements and the consequences for countries processes of structural change the results suggest a clear role for fertilizer modern seeds and water in boosting yields we then test for respective empirical links between agricultural yields and economic growth labor share in agriculture and non agricultural value added per worker the identification strategy includes a novel instrumental variable that exploits the unique economic geography of fertilizer production and transport costs to countries agricultural heartlands we estimate that a half ton increase in staple yields generates a 14 to 19 percent higher gdp per capita and a 4 6 to 5 6 percentage point lower labor share in agriculture five years later the results suggest a strong role for agricultural productivity as a driver of structural change

semiparametric estimation and consumer demand this paper considers the implementation of semiparametric methods in the empirical analysis of consumer demand the application is to the estimation of the engel curve relationship and uses the british family expenditure survey household composition is modelled using an extended partially linear framework this is shown to provide a useful method for pooling non parametric engel curves across households of different demographic composition c 1998 john wiley sons ltd

tricks with hicks the easi demand system we invent implicit marshallian demands which combine desirable features of hicksian and marshallian demands we propose and estimate the exact affine stone index easi implicit marshallian demand system like the almost ideal demand aid system easi budget shares are linear in parameters given real expenditures however unlike the aid easi demands can have any rank and its engel curves can have any shape over real expenditures easi error terms equal random utility parameters to account for unobserved preference heterogeneity easi demand functions can be estimated using gmm or three stage least squares and like aid an approximate easi model can be estimated by linear regression

input subsidy programs in sub saharan africa a synthesis of recent evidence input subsidy programs have once again become a major plank of agricultural development strategies in africa ten african governments spend roughly us 1 billion annually on input subsidy programs isps amounting to 28 6 of their public expenditures on agriculture this article reviews the microlevel evidence on isps undertaken since the mid 2000s we examine the characteristics of subsidy beneficiaries crop response rates to fertilizer application and their influence on the performance of subsidy programs the impacts of subsidy programs on national fertilizer use and the development of commercial input distribution systems and finally the impact of isps on food price levels and poverty rates the weight of the evidence indicates that the costs of the programs generally outweigh their benefits findings from other developing areas with a higher proportion of crop area under irrigation and with lower fertilizer prices factors that should provide higher returns to fertilizer subsidies than in africa indicate that at least a partial reallocation of expenditures from fertilizer subsidies to r d and infrastructure would provide higher returns to agricultural growth and poverty reduction however because isps enable governments to demonstrate tangible support to constituents they are likely to remain on the african landscape for the foreseeable future hence the study identifies ways in which benefits can be enhanced through changes in implementation modalities and complementary investments within a holistic agricultural intensification strategy among the most important of these are efforts to reduce the crowding out of commercial fertilizer distribution systems and programs to improve soil fertility to enable farmers to use fertilizer more efficiently the challenges associated with achieving these gains are likely to be formidable

a periodic review production planning model with uncertain capacity and uncertain demand optimality of extended myopic policies increasing product complexity manufacturing environment complexity and an increased emphasis on product quality are all factors leading to uncertainties in production processes these uncertainties are in the form of unplanned machine maintenance varying production yields and rework among others in planning for production an adequate model must incorporate these uncertainties into the representation of the production process this paper treats the aggregate planning problem for a single product with random demand and random capacity in the single period problem random capacity does not affect the optimal policy but results in a unimodal nonconvex cost function in the multiple period and infinite horizon settings order up to policies that are dependent on the distribution of capacity are shown to be optimal in spite of a nonconvex cost in the infinite horizon setting an intuitive description of the situation leads to the notion of a class of extended myopic policies requiring the consideration o

estimating the value and distributional effects of free state schooling the effects of free of charge state education on income distribution are often studied by allocating government education outlays to households assuming that these outlays equal the benefit which households attach to state schooling this paper proposes a demand analysis approach to estimating the true value of state education as perceived by consumers and uses the results to assess the inefficiency of public provision empirical analysis based on data from cyprus suggests that state schooling costs twice the amount households are willing to pay for the implications of this finding for the equality and anti poverty effects of state education are illustrated

carbon tax simulations using a household demand model abstract the main objective of this paper is to analyse consumer response and welfare effects due to changes in energy or environmental policy to achieve this objective we formulate and estimate an econometric model for non durable consumer demand in sweden that utilises micro and macro data in the simulations we consider two revenue neutral scenarios that both imply a doubling of the co2 tax one that returns the revenues in the form of a lower vat and one that subsidise public transport one conclusion from the simulations is that the co2 tax has regional distribution effects in the sense that household living in sparsely populated areas carry a larger share of the tax burden

new estimates of the elasticity of marginal utility for the uk this paper provides novel empirical evidence on the value of the elasticity of marginal utility eta for the united kingdom eta is a crucial component of the social discount rate sdr which determines the inter temporal trade offs that are acceptable to society using contemporaneous and historical data new estimates are obtained using four revealed preference techniques the equal sacrifice income tax approach the euler equation approach the frisch additive preferences approach and risk aversion in insurance markets a meta analysis indicates parameter homogeneity across approaches and a central estimate of 1 5 for eta the confidence interval excludes unity the value used in official guidance by the uk government the term structure of the sdr is then estimated the result is a short run sdr of 4 5 declining to 4 2 in the very long run this is higher and flatter than the uk official guidance the difference stems from incorrect calibration of social welfare and estimation of the diffusion of growth other things equal the results suggest that current uk guidance might need to be updated

optimal production and inventory policy for multiple products under resource constraints we show that a modified base stock policy is optimal for multiproduct infinite horizon production inventory systems where demand for the products is random and the products share a finite resource every period we characterize the optimal policy for the case of homogeneous products because of the difficulty in computing the optimal base stock levels for the heterogeneous case we propose a heuristic that is simple enough for practical applications we present numerical results that suggest that the heuristic yields near optimal solutions

nesting the aids and translog demand systems this paper shows that there exists a relatively simple demand model that is consistent with utility maximization and has nested within it both the almost ideal demand system and translog models this model is exactly aggregated then estimated using aggregate u s demand data the results are used to test the relative adequacy of the almost ideal demand system and translog models copyright 1989 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

a life cycle consistent empirical model of family labour supply using cross section data this paper estimates a utility maximising model of the joint determination of male and female labour supplies using a sample of married couples from the u k family expenditure survey the emphasis is on the estimation of within period preferences that are consistent with intertemporal two stage budgeting under uncertainty however the approach we adopt provides an alternative method of estimating certain aspects of life cycle behaviour to the fixed effects constant approach of heckman and macurdy 1980 macurdy 1981 and browning deaton and irish 1985 moreover it relaxes some of the underlying restrictions that are implicit in these constant models under uncertainty

best nonparametric bounds on demand responses this paper uses revealed preference inequalities to provide the tightest possible best nonparametric bounds on predicted consumer responses to price changes using consumer level data over a finite set of relative price changes these responses are allowed to vary nonparametrically across the income distribution this is achieved by combining the theory of revealed preference with the semiparametric estimation of consumer expansion paths engel curves we label these expansion path based bounds on demand responses as e bounds deviations from revealed preference restrictions are measured by preference perturbations which are shown to usefully characterize taste change and to provide a stochastic environment within which violations of revealed preference inequalities can be assessed

how serious is the aggregation problem an empirical illustration heterogeneity in consumer behaviour may create problems with aggregation across consumers if so we may not be able to make correct inferences about behaviour based on aggregated data however using micro estimates to predict aggregate demand responses to policy changes may also create a bias if not aggregated properly this may sound like a catch 22 situation but it is not as it is possible to calculate both micro and aggregate demand responses based on microdata the size of the aggregation bias is an empirical question in this article we show how to calculate theoretically consistent aggregate demand responses we use both micro and macro data for norwegian household electricity consumption to illustrate the magnitude and direction of different aggregation biases we find considerable aggregation biases in particular when estimating with macro data

state conditional fertilizer yield response on western kenyan farms 15 16 17 we acknowledge with gratitude support from the rockefeller foundation the united states agency for 18 international development usaid leadership enhancement in agriculture program leap and the 19 coupled natural and human systems program of the biocomplexity initiative of the national science 20 foundation through grant bcs 0215890 the world agroforestry center icraf graciously hosted 21 the lead author for part of the research and provided soil test results we are also grateful to james

a non stationary periodic review production inventory model with uncertain production capacity and uncertain demand abstract in this paper we consider a nonstationary periodic review dynamic production inventory model with uncertain production capacity and uncertain demand the maximum production capacity varies stochastically it is known that order up to or base stock critical number policies are optimal for both finite horizon problems and infinite horizon problems we obtain upper and lower bounds of the optimal order up to levels and show that for an infinite horizon problem the upper and the lower bounds of the optimal order up to levels for the finite horizon counterparts converge as the planning horizons considered get longer furthermore under mild conditions the differences between the upper and the lower bounds converge exponentially to zero

estimating a demand system with nonnegativity constraints mexican meat demand a new information based approach for estimating systems of many equations with nonnegativity constraints is presented this approach called generalized maximum entropy gme is more practical and

what is the aggregate economic rate of return to foreign aid in recent years academic studies have been converging towards the view that foreign aid promotes aggregate economic growth we employ a simulation approach to i validate the coherence of empirical aid growth studies published since 2008 and ii calculate plausible ranges for the rate of return to aid our results highlight the long run nature of aid financed investments and the importance of channels other than accumulation of physical capital we find the return to aid lies in ranges commonly accepted for public investments and there is little to justify the view that aid has had a significant pernicious effect on productivity

a capacitated production inventory model with periodic demand for a single product single stage capacitated production inventory model with stochastic periodic cyclic demand we find the optimal policy and characterize some of its properties we study the finite horizon the discounted infinite horizon and the infinite horizon average cases a simulation based optimization method is provided to compute the optimal parameters based on a numerical study several insights into the model are also provided

welfare comparison under exact aggregation new econometric model of aggregate consumer behavior in the united states and to apply this model to the analysis of impacts of alternative economic policies on the welfare of individual consuming units the model incorporates time series data on quantities consumed prices the level and distribution of income and demographic characteristics of the population it also incorporates cross section data on the allocation of consumer expenditures for households with different demographic characteristics our econometric model is based on the theory of exact aggregation developed by lau 1977a c this theory makes it possible to dispense with the notion of a representative consumer in constructing models of aggregate consumer behavior one of the most remarkable implications of lau s theory of exact aggregation is that systems of demand functions for individuals with common demographic characteristics can be recovered uniquely from the system of aggregate demand functions using the individual demand functions we can analyze the impact of economic policy on consumer welfare

individual versus aggregate income elasticities for heterogeneous populations summary this paper deals with different concepts of income elasticities of demand for a heterogeneous population and the relationship between individual and aggregate elasticities in general the aggregate elasticity is not equal to the mean of individual elasticities the difference depends on the heterogeneity of the population and is quantified by a covariance term sign and magnitude of this term are determined by an empirical analysis based on the uk family expenditure survey it is shown that the relevant quantities can be identified from cross sectional data and without imposing restrictive structural assumptions can be estimated by nonparametric techniques it turns out that the aggregate elasticity significantly overestimates the mean of individual elasticities for many commodity groups copyright 2011 john wiley sons ltd

the contributions of angus deaton angus deaton was awarded the 2015 sveriges riksbank prize in economic sciences in memory of alfred nobel for his analysis of consumption poverty and welfare this article reviews his contributions to economics

static and intertemporal household decisions we discuss the most popular static and dynamic models of household behavior our main objective is to explain which aspects of household decisions different models can account for using this insight we describe testable implications identification results and estimation findings obtained in the literature particular attention is given to the ability of different models to answer various types of policy questions

allocating production capacity among multiple products we consider the problem of allocating production capacity among multiple items assuming that a fixed proportion of overall capacity can be dedicated exclusively to the production of each item given a capacity allocation production of each item follows a base stock policy i e each demand triggers a replenishment order to restore safety stocks to target levels we present procedures for choosing base stock levels and capacity allocations that are asymptotically optimal our objective is to minimize holding and backorder costs or to minimize holding costs subject to a service level constraint asymptotic optimality refers to large backorder penalties or stringent service level constraints numerical results indicate that our rules perform very well even far from the asymptotic regime a further approximation step results in allocation rules based on heavy traffic limits these too perform well

simple tests of distributional effects on macroeconomic equations the presence of distributional effects in macroeconomic equations is shown to coincide with nonlinearity in micro behavioral relationships parameters estimated with aggregate data as in representative agent models contain distributional biases that are not measurable using aggregate data alone tests for distributional effects and other measures of the extent of aggregation problems are derived using distributional data observed over time significant distributional effects are noted for a model of annual aggregate u s commodity expenditure data a static model that accommodates individual heterogeneity is found to be statistically equivalent to a simply dynamic model that accommodates first order autocorrelation

how revealing is revealed preference this lecture address the following two key criticisms of the empirical application of revealed preference theory when the rp conditions do not reject they do not provide precise predictions and when they do reject they do not help characterize the nature of irrationality or the degree direction of changing tastes recent developments in the application of rp theory are shown to have rendered these criticisms unfounded a powerful test of rationality is available that also provides a natural characterization of changing tastes tight bounds on demand responses and on the welfare costs of relative price and tax changes are also available and are shown to work well in practice

optimal joint inventory and transshipment control under uncertain capacity in this paper we address the optimal joint control of inventory and transshipment for a firm that produces in two locations and faces capacity uncertainty capacity uncertainty e g due to downtime quality problems yield etc is a common feature of many production systems but its effects have not been explored in the context of a firm that has multiple production facilities we first characterize the optimal production and transshipment policies and show that uncertain capacity leads the firm to ration the inventory that is available for transshipment to the other location and characterize the structure of this rationing policy then we characterize the optimal production policies at both locations which are defined by state dependent produce up to thresholds we also describe sensitivity of the optimal production and transshipment policies to problem parameters and in particular explain how uncertain capacity can lead to counterintuitive behavior such as produce up to limits decreasing for locations that face stochastically higher demand we finally explore through a numerical study when the optimal policy is most likely to yield significant benefits compared to simple policies

toward a green revolution in africa what would it achieve and what would it require the current global food crisis has reemphasized the costliness of africa s failure to achieve food security and poverty reduction the instrument by which other more successful developing countries achieved these outcomes was a green revolution in agriculture while previous research has provided largely discursive appraisals of the viability of an african green revolution this article adopts a more rigorous methodology to address that question first an economy wide multimarket model augmented with existing poverty growth elasticities is developed to assess the likely impacts of a rapid acceleration in food production of the kind witnessed in previous green revolutions on food prices consumption and demand farmer revenue and poverty our results suggest that a rapid growth in staple production together with more integrated regional markets would reduce food prices by roughly 20 40 for consumers and 10 20 for producers among the major crops this translates into a large rise in farm revenues annual agricultural growth rates of 6 5 or higher broader income growth and food security and over 70 million africans being lifted out of poverty the article concludes by emphasizing the kinds of fundamental policy actions and resources that would be required for achieving these outcomes

agriculture aid and economic growth in africa how can foreign aid to agriculture support economic growth in africa this paper constructs a geographically indexed applied general equilibrium model that considers pathways through which aid might affect growth and structural transformation of labor markets in the context of soil nutrient variation minimum subsistence consumption requirements domestic transport costs labor mobility and constraints to self financing of agricultural inputs using plausible parameters the model is presented for uganda as an illustrative case three stylized scenarios demonstrate the potential economy wide impacts of both soil nutrient loss and replenishment and how foreign aid can be targeted to support agricultural inputs that boost rural productivity and shift labor to boost real wages one simulation shows how a temporary program of targeted official development assistance oda for agriculture could generate contrary to traditional dutch disease concerns an expansion in the primary tradable sector and positive permanent productivity and welfare effects leading to a steady decline in the need for complementary oda for budget support

aggregation and labor supply elasticities aggregation and labor supply elasticities the aggregate frisch elasticity of labor supply has played a key role in business cycle analysis this paper develops a statistical aggregation procedure which allows for worker heterogeneity in observables and unobservables and is applicable to an individual labor supply function with non employment as a possible outcome performing a thought experiment in which all offered or paid wages are subject to an unanticipated temporary change we can derive an analytical expression for the aggregate frisch elasticity and illustrate its main components i the intensive and extensive adjustment of hours worked ii the extensive adjustment of wages and iii the aggregate employment rate we use individual specific data from the german socio economic panel soep for males at working age in order to quantify each component this data base provides indirect evidence on non employed workers reservation wages we use this variable in conjunction with a twostep conditional density estimator to retrieve the extensive adjustment of hours worked and wages paid the intensive hours adjustment follows from estimating a conventional panel data model of individual hours worked our estimated aggregate frisch elasticity varies between 63 and 70 these results are sensitive to the assumed nature of wage changes jel classification c51 e10 j22

structural adjustment and soil degradation in tanzania a cge model approach with endogenous soil productivity abstract in this paper a model of the nitrogen cycle in the soil is incorporated in a computable general equilibrium cge model of the tanzanian economy thus establishing a two way link between the environment and the economy for a given level of natural soil productivity profit maximising farmers choose input levels and hence production volumes which in turn influence soil productivity in the following years through the recycling of nitrogen from the residues of roots and stover and the degree of erosion the model is used to simulate the effects of typical structural adjustment policies like a reduction in agro chemicals subsidies reduced implicit export tax rate etc after 10 years the result of a joint implementation is a 9 higher gross domestic product gdp level compared to the baseline scenario the effect of soil degradation is found to represent a reduction in the gdp level of more than 5 for the same time period

the effects of male and female labor supply on commodity demands we examine the effects of male and female labor supply on household demands and present a simple and robust test for the separability of commodity demands from labor supply using data on individual households from six years of the uk fes we estimate a demand system for seven goods which includes hours and participation dummies as conditioning variables allowance is made for the possible endogeneity of these conditioning labor supply variables we find that separability is rejected furthermore we present evidence that ignoring the effects of labor supply leads to bias in the parameter estimates

aggregation with log linear models when economic theory suggests a log linear specification for individual agents e g cobbdouglas production it is common to estimate the same log linear model with aggregate data invoking a representative agent assumption and thereby assuming away aggregation errors this paper gives necessary and sufficient restrictions on the distribution of agents in an economy for log linear agent models to aggregate into log linear macro models and discusses the aggregation bias resulting from violation of these restrictions theorems tests economic rationales and empirical results are given included are connections to random walks and to cointegration analogous results for log level models are derived

flexible and semiflexible consumer demands with quadratic engel curves in this paper we introduce three flexible consumer demand systems in which expenditures on goods are quadratic functions of income we view these alternatives as to the demand systems used heretofore in the empirical modeling of rank three demands namely those in which expenditure shares are quadratic functions of the logarithm of income curvature conditions required by theory can be imposed locally during the estimation for each and a semiflexible version can be estimated for illustrative purposes we estimate various forms of two of the systems using canadian data on seven categories of goods for the period 1947 to 1995

nudging farmers to use fertilizer theory and experimental evidence from kenya we model farmers as facing small fixed costs of purchasing fertil izer and assume some are stochastically present biased and not fully sophisticated about this bias such farmers may procrastinate post poning fertilizer purchases until later periods when they may be too impatient to purchase fertilizer consistent with the model many farmers in western kenya fail to take advantage of apparently profit able fertilizer investments but they do invest in response to small time limited discounts on the cost of acquiring fertilizer free deliv ery just after harvest calibration suggests that this policy can yield higher welfare than either laissez faire policies or heavy subsidies

explaining african economic performance africa has had slow growth and a massive exodus of capital in many respects it has been the most capital hostile region we review and interpret the aggregate level and microeconomic literatures to identify the key explanations for this performance there is a reasonable correspondence of the two sets of evidence pointing to four factors as being important these are a lack of openness to international trade a high risk environment a low level of social capital and poor infrastructure these problems are to a substantial extent attributable to government behaviour and the paper includes a review of the political economy literature which addresses that behaviour

aggregate behavior and microdata abstract it is shown how one can effectively use microdata in modelling the change over time in an aggregate e g mean consumption expenditure of a large and heterogeneous population the starting point of our aggregation analysis is a specification of explanatory variables on the micro level typically some of these explanatory variables are observable and others are unobservable based on certain hypotheses on the evolution over time of the joint distributions across the population of these explanatory variables we derive a decomposition of the change in the aggregate which allows a partial analysis to isolate and to quantify the effect of a change in the observable explanatory variables this analysis does not require an explicit treatment of the unobservable variables

the optimality of hedging point policies for stochastic two product flexible manufacturing systems this paper studies the stochastic two item periodic review single facility flexible manufacturing systems where stochasticity comes from random demands or and unreliable production process based on a notion called difference monotone introduced in this paper we prove that the hedging point policy is optimal to the systems in general for both finite and infinite horizon cases of the problems this result is demand distribution free and does not require strict convexity or even differentiability of the one period expected cost function a general characterization of the hedging point policy together with monotone switching curves is provided

on the distributional effects of income in an aggregate consumption relation in this paper we analyse the influence of characteristics of the income distribution in modelling aggregate consumption expenditure we model the aggregate consumption relation of a heterogeneous population using a statistical distributional approach of aggregation and apply it to uk family expenditure survey data a bootstrap test based on a non parametric estimation methodology which accounts for the presence of continuous and discrete variables suggests that the mean and the dispersion of the income distribution significantly influence aggregate consumption expenditure also the parameters of the aggregate relation are time varying these findings have implications for constructing empirically sound models of aggregate consumption expenditure dans ce memoire on analyse l influence des caracteristiques de la repartition des revenus dans la modelisation des depenses agregees de consommation on examine la relation de consommation agregee d une population heterogene a l aide d une approche a l agregation fondee sur une distribution statistique et on applique le modele aux donnees d une enquete sur les depenses des menages au royaume uni un test de type bootstrap construit sur une methodologie d estimation non parametrique et qui tient compte de la presence de variables continues et discretes suggere que la moyenne et la dispersion de la distribution des revenus influencent de maniere significative les depenses de consommation agregees les parametres de cette relation agregee sont sensibles au temps ces resultats ont des implications pour la construction de modeles empiriques fiables de la relation agregee des depenses de consommation

dynamic product portfolio management with life cycle considerations we consider a portfolio of products in which each product probabilistically transitions through various life cycle stages the evolution through these life cycle stages is impacted by both marketing support and product launch decisions which are bound by a financial constraint in the form of restricted working capital in the model the joint working capital level serves to finance the portfolio expenditures and is decided a priori by the company we use an infinite horizon markov decision process mdp to find the optimal decisions to coordinate the operations and finance depending on the composition of the portfolio we find that the policy optimizing the product launch marketing support and inventory decisions under a working capital constraint is independent of the correlation between demand levels of the products in the portfolio we numerically demonstrate that the joint management of the products has a significant positive effect on the total profit reducing the amount of working capital used per product we also show that the optimal policy smooths aggregated demand levels as well as cash flows

achieving the millennium development goals in sub saharan africa a macroeconomic monitoring framework this paper presents a macroeconomic approach to monitoring progress toward achieving the millennium development goals mdgs in sub saharan africa at the heart of our framework is a macro model which captures key linkages between foreign aid public investment disaggregated into education infrastructure and health the supply side and poverty the model is then linked through cross country regressions to indicators of malnutrition infant mortality life expectancy and access to safe water a composite mdg indicator is also calculated the functioning of our framework is illustrated by simulating the impact of an increase in foreign aid to niger at the mdg horizon of 2015 under alternative assumptions about the degree of efficiency of public investment our approach can serve as the building block for strategy papers for human development spahd a more encompassing concept than the current poverty reduction strategy papers

aid dutch disease and manufacturing growth abstract we examine the effects of aid on the growth of manufacturing using a methodology that exploits the variation within countries and across manufacturing sectors and corrects for possible reverse causality we find that aid inflows have systematic adverse effects on a country s competitiveness as reflected in the lower relative growth rate of exportable industries we provide some evidence suggesting that the channel for these effects is the real exchange rate appreciation caused by aid inflows we conjecture that this may explain in part why it is hard to find robust evidence that foreign aid helps countries grow

the evolving role of agriculture in poverty reduction an empirical perspective abstract the role of agriculture in development remains much debated this paper takes an empirical perspective and focuses on poverty as opposed to growth alone the contribution of a sector to poverty reduction is shown to depend on its own growth performance its indirect impact on growth in other sectors the extent to which poor people participate in the sector and the size of the sector in the overall economy bringing together these different effects using cross country econometric evidence indicates that agriculture is significantly more effective in reducing poverty among the poorest of the poor as reflected in the 1 day squared poverty gap it is also up to 3 2 times better at reducing 1 day headcount poverty in low income and resource rich countries including those in sub saharan africa at least when societies are not fundamentally unequal however when it comes to the better off poor reflected in the 2 day measure non agriculture has the edge these results are driven by the much larger participation of poorer households in growth from agriculture and the lower poverty reducing effect of non agriculture in the presence of extractive industries

managing inventory with multiple products lags in delivery resource constraints and lost sales a mathematical programming approach this paper develops an order up tos inventory model that is designed to handle multiple items resource constraints lags in delivery and lost sales without sacrificing computational simplicity mild conditions are shown to ensure that the expected average holding cost and the expected average shortage cost are separable convex functions of the order up to levels we develop nonparametric estimates of these costs and use them in conjunction with linear programming to produce what is termed the lp policy the lp policy has two major advantages over traditional methods first it can be computed in complex environments such as the one described above and second it does not require an explicit functional form of demand something that is difficult to specify accurately in practice in two numerical experiments designed so that optimal policies could be computed the lp policy fared well differing from the optimal profit by an average of 2 20 and 1 84 respectively these results compare quite favorably with the errors incurred in traditional methods when a correctly specified distribution uses estimated parameters our findings support the effectiveness of this mathematical programming technique for approximating complex real world inventory control problems

production and inventory control for a make to stock calibrate to order system with dedicated and shared resources consider a firm that produces multiple products on dedicated production lines stage 1 which are further customized calibrated on a shared resource stage 2 common to all products the dedicated production lines and the shared resource for calibration face capacity uncertainties the firm holds inventory of products that are not yet calibrated and carries out calibration when an order is received we analyze a multiperiod inventory model for two products and derive the optimal production policy at stage 1 as well as the optimal allocation of the shared resource to demands at stage 2 for the shared resource because of its capacity uncertainty not only the total planned production quantities matter but also the sequence in which the products are processed we characterize the optimal allocation of the shared resource and show that the optimal policy keeps the ending inventories of products as close to a so called target path as possible for the dedicated production lines because of their capacit

a multi product risk averse newsvendor with exponential utility function abstract we consider a multi product newsvendor using an exponential utility function we first establish a few basic properties for the newsvendor regarding the convexity of the model and monotonicity of the impact of risk aversion on the solution when the product demands are independent and the ratio of the degree of risk aversion to the number of products is sufficiently small we obtain closed form approximations of the optimal order quantities the approximations are as easy to compute as the risk neutral solution we prove that when this ratio approaches zero the risk averse solution converges to the corresponding risk neutral solution when the product demands are positively negatively correlated we show that risk aversion leads to lower higher optimal order quantities than the solution with independent demands using a numerical study we examine convergence rates of the approximations and thoroughly study the interplay of demand correlation and risk aversion the numerical study confirms our analytical results and further shows that an increased risk aversion does not always lead to lower order quantities when demands are strongly negatively correlated

discrete order admission atp model with joint effect of margin and order size in a mto environment abstract swarming demands and seasonality periodically induce a stringent capacity problem in the made to order mto b2b environment desirable order admission is a tactic with minimal application cost for handling this problem a real time order admission problem with limited major customer population and batch size demand with heterogeneous distributions is modeled as a dynamic and stochastic knapsack problem the optimality of the markovian deterministic reward threshold policy is verified optimal policy basic policy and the capacity rationing method are compared in the designed experiment the numerical results suggest great potential for increasing profit using the optimal order admission policy for mto businesses

estimation of complete demand systems from household budget data the linear and quadratic expenditure systems in this paper we explore two issues in empirical demand analysis the estimation of complete systems of demand equations using household budget data section i and the incorporation of demographic characteristics into such systems section ii although there are numerous studies which use time series data to estimate complete demand systems and many which estimate engel curves from household budget data there are virtually none which combine budget data from different periods to estimate complete systems since each budget study corresponds to a single price situation one might conjecture that estimation of complete systems would not be possible unless budget studies were available from a large number of periods this is incorrect in section i we argue that interesting complete demand systems can be estimated from a small number of budget studies despite the limited price variability represented in such data to demonstrate this we use budget study data for two periods to estimate a pair of related demand systems the familiar linear expenditure system les and a quadratic expenditure system qes a generalization of les in which the demand equations are quadratic in total expenditure the inclusion of demographic variables in the analysis of household consumption patterns is desirable because there are likely to be systematic differences in the consumption behavior of households with different demographic characteristics but the effects of demographic characteristics have seldom been studied within the framework of complete demand systems in section ii we propose translating as a general method for incorporating demographic variables into complete systems of demand equations this method has not previously been discussed as a general technique for bringing demographic variables into demand systems although it has been employed in several studies to improve the estimates of the les and the qes presented in section i we reestimate these two systems using translating to incorporate family size

the welfare effects and the distributive impact of carbon taxation on italian households in this work the welfare effects and the distributive impact on italian households of the italian carbon tax are calculated the carbon tax has been introduced in italy at the beginning of 1999 asking for smooth increases over a number of years in the prices of most fossil fuels its welfare effects have been calculated using true cost of living index numbers and the compensating variation the parameters have been obtained through estimation of a complete almost ideal demand system using households data from 1985 to 1996 the welfare loss turns out to be quite substantial and affects italian households in a non negligible way but the distribution of welfare losses across different levels of total monthly expenditures does not allow sustaining the regressivity of carbon taxation as the effect becomes bigger as we move up the income distribution this evidence might encourage the use of carbon taxes at least in the transport sector as cost effective instruments of environmental policy especially after the ratification of the kyoto protocol on climate change

aid and growth what does the cross country evidence really show abstract we examine the effects of aid on growth in cross sectional and panel data after correcting for the possible bias that poorer or stronger growth may draw aid contributions to recipient co

what do we learn about consumer demand patterns from micro data the aim of this paper is to assess the importance of using micro level data in the econometric analysis of consumer demand to do this we utilize a time series of repeated cross sections covering some 4 000 households in each of 15 years employing a number of different aggregation procedures we conclude that aggregate data alone are unlikely to produce reliable estimates of structural price and income coefficients however once certain aggregation factors as well as trend and seasonal components are included an aggregate model is not necessarily outperformed across all demand equations in terms of forecasting ability jel d12 c52 c31 the purpose of this paper is to develop a complete consumer demand system based on a time series of individual household data and to use it to measure the biases introduced into the study of consumer de mand behavior when aggregate data are used in place of the appropriate microeco nomic data we assess the suitability of ag gregate data through the impact on income and price elasticities and by evaluating the ability of both micro and aggregate based models to forecast aggregate consumer de mand the biases introduced by the use of aggregate data depend upon the way that household characteristics interact with in come and price effects and on departures of demand systems from linearity we explore the structure of microeconomic demand sys tems and the role of household characteris tics in the behavior of consumer demand both for the light this may shed on the pattern of future demands and for the im plications this behavior has for issues of aggregation consumer demand patterns typically found in micro data sets vary considerably across households with different household characteristics and with different levels of income we model this variability by making intercept and slope parameters in the budget share equations of our demand sys tem depend on household characteristics and by allowing for nonlinear total log expenditure terms in fact in theory consistent demand systems it is total ex penditure rather than disposable income that is allocated across goods we find that this general framework leads to a well specified data coherent demand system which is a quadratic extension of the popu lar almost ideal model of angus s deaton and john muellbauer 1980 the micro level estimates are shown to be sensitive to the treatment of endogeneity of total expen diture and to the specification of interaction terms with household characteristics in ad dition this specification is also shown to possess many attractive features for the evaluation of aggregate models

preference heterogeneity and the rank of demand systems this article examines the effect of preference heterogeneity on nonparametric and parametric tests of the rank of demand systems using samples of households drawn from the u k family expenditure survey we find that preference heterogeneity increases the rank of demand systems when the effects of household characteristics on demand are removed by semiparametric techniques a rank 3 demand system appears to be an adequate empirical specification for all samples

aid and growth regressions this paper examines the relationship between foreign aid and growth in real gdp per capita as it emerges from simple augmentations of popular cross country growth specifications it is shown that aid in all likelihood increases the growth rate and this result is not conditional on good policy there are however decreasing returns to aid and the estimated effectiveness of aid is highly sensitive to the choice of estimator and the set of control variables when investment and human capital are controlled for no positive effect of aid is found yet aid continues to impact on growth via investment we conclude by stressing the need for more theoretical work before this kind of cross country regressions are used for policy purposes

quadratic engel curves and consumer demand this paper presents a model of consumer demand that is consistent with the observed expenditure patterns of individual consumers in a long time series of expenditure surveys and is also able to provide a detailed welfare analysis of shifts in relative prices a nonparametric analysis of consumer expenditure patterns suggests that engel curves require quadratic terms in the logarithm of expenditure while popular models of demand such as the translog or the almost ideal demand systems do allow flexible price responses within a theoretically coherent structure they have expenditure share engel curves that are linear in the logarithm of total expenditure we derive the complete class of integrable quadratic logarithmic expenditure share systems a specification from this class is estimated on a large pooled data set of u k households models that fail to account for engel curvature are found ro generate important distortions in the patterns of welfare losses associated with a tax increase

aid and the supply side public investment export performance and dutch disease in low income countries contemporary policy debates on the macroeconomics of aid often concentrate on short run dutch disease effects ignoring the possible supply side impact of aid financed public expenditure in the simple model of aid and public expenditure presented here public infrastructure generates an inter temporal productivity spillover which may exhibit a sector specific bias the model also provides for a learning by doing externality through which total factor productivity in the tradable sector is an increasing function of past export volumes an extended computable version of this model is used to simulate the effect of a step increase in net aid flows the simulations show that beyond the short run when conventional demand side dutch disease effects are present the relationship between enhanced aid flows and real exchange rates output growth and welfare is less straightforward than simple models of aid suggest public infrastructure investment that generates a productivity bias in favor of non tradable production delivers the largest aggregate return to aid but at the cost of deterioration in the income distribution income gains accrue predominantly to skilled and unskilled urban households leaving the rural poor relatively worse off under plausible parameterizations of the model the rural poor may also be worse off in absolute terms