the determinants and the selection of mexico us migrants using data from the mexican family life survey mxfls a panel of mexican individuals interviewed in 2002 and 2005 we analyze the characteristics of migrants from mexico to the us relative to non migrates and those who migrated and subsequently returned to mexico using pre and post migration earnings and their earnings in the us from the american community survey acs we characterize the selection of migrants on observable and non observable characteristics merging the data with us american community survey data we can also measure the expected earnings premium of migration to the us and the earnings premium for those that returned to mexico we find that migrants respond to the expected earnings premium to migration once we control for migration costs also the structure of the premium across skill groups generates negative selection on average and it can explain selection on observable and unobservables we also find that returnees are more positively selected over skills than migrants to the us initial poverty old age and family ties are strong deterrents of migration to the us once we account for the skill specific migration premium we also fi nd as trong under representation of college educated among migrants to the us possibly a consequence of the fact that undocumented migration is not an attractive option for those individuals

joint pricing and ordering policy for two echelon imperfect production inventory model with two cycles abstract this study deals with an imperfect epq economic production quantity price dependent inventory model over two types of cycles in the first cycle the retailer sells only good product with actual price and in the second he sells the products with a discount price in the production run time the non conforming items are produced at a random rate and they are reworked after the regular production run time and the reworked items are almost perfect as good as original quality items the retailer starts the second cycle when a certain percent of good items are left to him after the completion of regular production the retailer continues simultaneously two cycles up to which both types of the products are available to him now our objective is to find out optimal ordering lot size and optimal price for which the profit of the integrated model is maximum also we check the best strategy of retailer for the time of starting second cycle a numerical example is provided to illustrate the behavior and application of the model

economic order quantity models for imperfect items with buy and repair options abstract one of the celebrated extensions of the economic order production quantity eoq epq model is one that assumes a received shipment contains a fraction of imperfect non conforming quality items where these items detected by 100 screening are sold as a single batch at a discounted price this paper revisits this model salameh and jaber 2000 int j prod econ 64 1 59 64 and extends it by assuming that a shipment is coming from a distant supplier and therefore it is not feasible to replace the imperfect items with an additional order to the same supplier to address this restriction two models are presented the first assumes that imperfect items are sent to a repair shop who charges a cost plus a markup margin while the second model assumes that imperfect items are replaced by good ones from a local supplier at a higher cost the inventory environment assumed in this paper is relevant in todays globalised supply chains thus practical implications of the problem faced are discussed numerical results are also presented and discussed the results show that there exists a threshold value of the unit purchase cost of an emergency ordered item and a fraction of defectives to which it is decided to either buy or repair

old problems in the new solutions politically motivated allocation of program benefits and the new fertilizer subsidies summary fertilizer subsidies have been reinstituted in many african countries with innovations seeking to avoid the downsides of past programs the new subsidy paradigm however does not address how to curtail political manipulation which exacerbated inefficiencies of previous programs this paper analyzes whether politics affected voucher allocations in ghana s 2008 fertilizer subsidy program we find that more vouchers were targeted to districts that the ruling party had lost in the previous presidential elections and more so in districts that had been lost by a higher percentage margin this evidence shows that a significant threat to the efficiency of fertilizer subsidies remains

note on economic production quantity model for items with imperfect quality a practical approach abstract in this note we present a simple approach for determining the economic production quantity for an item with imperfect quality we compare the results based on the simple approach with the optimal method for determining the lot size and show that almost optimal results are obtained using the simple approach

emigration and wages in source countries evidence from mexico abstract this paper examines empirically the effect of mexican emigration to the united states on wages in mexico using data from the mexican and us censuses from 1970 to 2000 the main result in the paper is that emigration has a strong and positive effect on mexican wages there is also evidence for increasing wage inequality in mexico due to emigration simple welfare calculations based on a labor demand supply framework suggest that the aggregate welfare loss to mexico due to emigration is small however there is a significant distributional impact between labor and other factors

migration remittances and poverty in ecuador abstractwe analyse the influence of the recent wave of migration on the incidence of poverty among stayers in ecuador we draw our data from a survey that provides detailed information on migrants the analysis reveals a significant negative effect of migration on poverty among migrant households this effect is substantially smaller than the one that we find focusing on recipient households we explore the factors that account for this divergence our analysis entails that the existing empirical evidence on the relationship between remittances and poverty does not need to be informative about the size of the direct poverty reduction potential of migration

fiscal federalism and redistributive politics abstract we consider the interaction between redistributive politics at central and local levels in a federal system and characterize the factors influencing success in redistributive politics in both federal and unitary systems we examine how the political characteristics of different states and groups give them better or worse outcomes in a federal system as opposed to a unitary system we examine possibilities of multiple equilibria with divided government between the two layers we analyze the choice between block grants and matching grants we also examine the impact of federalism on the incentives for geographic mobility

eoq models for a coordinated two level international supply chain considering imperfect items and environmental impact abstract for a two level supply chain models are presented to determine the optimal production shipment policy for items with imperfect quality in three different scenarios a both the vendor and the buyer are in the same country b the vendor and the buyer are in different countries where the stochastic behavior of the exchange rate between the two countries is modeled using a mean reverting process and c environmental impact is incorporated in determining the optimal production shipment policy by taking into account the fixed and variable carbon emission costs the objective is to minimize the total expected cost per unit time for each scenario considering equal shipment size the total expected cost per unit time is derived and the solution procedure is proposed numerical examples are presented and the results are discussed

on gender gaps and self fulfilling expectations alternative implications of paid for training i introduction the recent literature on gender differences in the labor market has focused mainly on two issues the first one deals with the mechanisms e g adverse selection that can amplify initial differences in preferences or productivity across genders leading to sizeable gender gaps in wages labor force participation or working hours these models help us understand to what extent changes in gender gaps have been due to changes in fundamentals including differences in the pattern of endogenous accumulation of human capital by men and women 1 the second one is related to the channels explaining persistence in gender gaps even when exogenous differences across the sexes are of little importance or even absent 2 these studies tend to rely upon the existence of incentive problems in the labor market e g moral hazard leading to self fulfilling prophecies about differences in gender roles without assuming any initial comparative advantages our paper falls into this second strand of the literature by considering an alternative mechanism based on statistical discrimination by firms in the provision of paid for training to male and female workers this yields multiplicity of equilibria in gender gaps even in the absence of moral hazard 3 the basic idea in models of gender gaps relying upon self fulfilling prophecies is that employers beliefs about women s lower attachment to the labor market lead to wage differentials in favor of men hence since women expect to face a lower expected opportunity cost they end up devoting more time to housework validating in this way firms beliefs for example albanesi and olivetti 2009 propose a model where firms are subject to incentive compatible constraints due to their imperfect monitoring of workers effort a moral hazard problem and of hours of housework an adverse selection problem as a result different types of labor contracts are offered to men and women in a similar vein lommerud and vagstad 2007 deal with a model where firms allocate workers to fast and slow track jobs the former requiring a fixed investment cost if women have traditionally exerted primary major responsibility at home and wages are non contractible they will predominantly follow a mommy track in equilibrium while incentive problems often used to derive additional predictions on the structure of wages to be confronted with the data provide a useful modeling device they could be somewhat restrictive for instance concerning the difficulty of perfectly monitoring effort pay gaps should be negligible for routine tasks performed by less skilled employees for whom effort and output should be easily observable yet even after removing differences in observable characteristics and in the overall wage dispersion there is evidence about substantial gender gaps in hourly wages in these categories see e g blau and kahn 2000 bassanini and saint martin 2008 de la rica et al 2008 our paper contributes to this literature by proposing a novel mechanism which does not rely on incentive problems we consider a two period model in which firms initially offer paid for training to workers taking as given the division of housework between spouses in the second period spouses decide on how to split the certain and uncertain parts of housework where the latter is captured by the realization of a shock affecting household tasks during this period e g unexpected need of housework or events that require parental leave etc both decisions interact because the housework decision determines whether a spouse works or quits after receiving training and the firm chooses the amount of training without observing the household s housework allocation statistical discrimination arises in this setup as a result of firms prior beliefs about which spouse is more likely to quit the job under the key assumptions that wages are predetermined with respect to housework shocks and that the household does not re optimize after the shock is revealed asymmetric beliefs will induce differences in the provision of training across spouses

issues in new political economy an overview a brief overview of the historical background nature and rapid growth in volume and scope of new political economy since the early 1980s is provided the paper continues with some general reflections on the strengths and weaknesses of the new political economy approach illustrated by the other contributions to this special issue of the journal of economic surveys the final section summarises these contributions

can democracy induce development a constitutional perspective we examine the constitutional design required for democratic societies to overcome poverty traps restricting agenda setting by ensuring subsistence levels of consumption and applying simple majority voting as a decision rule will not enable a society to overcome poverty we show that a combination of suitable constitutional rules can however overcome poverty and induce economic well being besides majority voting these rules include rotating agenda setting agenda repetition and tax protection rules we thus highlight the crucial role of democratic institutions for economic development

an economic order quantity model with defective items and shortages abstract the fundamental assumption of an economic order quantity eoq model is that 100 of items in an ordered lot are perfect this assumption is not always pertinent for production processes because of process deterioration or other factors this paper develops an eoq model for that each ordered lot contains some defective items and shortages backordered it is assumed that 100 of each lot are screened to separate good and defective items which are collection of imperfect quality and scrap items the effect of percentage defective on optimal solution is studied while numerical examples are provided for the developed model

multilateral resistance to migration the rate of migration observed between two countries does not depend solely on their relative attractiveness but also on the one of alternative destinations following the trade literature we term the influence exerted by other destinations on bilateral flows as multilateral resistance to migration and we show how it can be accounted for when estimating the determinants of migration rates in the context of a general individual random utility maximization model we propose the use of the common correlated effects estimator pesaran 2006 and apply it to high frequency data on the spanish immigration boom between 1997 and 2009 compared to more restrictive estimation strategies developed in the literature the bias goes in the expected direction we find a smaller effect of gdp per capita and a larger effect of migration policies on bilateral rates

incentives to cultivate favored minorities under alternative electoral systems a simple model is used to compare under different electoral systems the incentives for candidates to create inequalities among otherwise homogeneous voters by making campaign promises that favor small groups rather than appealing equally to all voters in this game model each candidate generates offers for voters independently out of a distribution that is chosen by the candidate subject only to the constraints that offers must be nonnegative and have mean 1 symmetric equilibria with sincere voting are analyzed for two candidate elections and for multicandidate elections under rank scoring rules approval voting and single transferable vote voting rules that can guarantee representation for minorities in multiseat elections generate in this model the most severely unequal campaign promises

an eoq model with imperfect quality items inspection errors shortage backordering and sales returns abstract in practice the items received in a lot may contain defective items and the screening process to eliminate the defective items may involve both a type i and a type ii error due to the defective items and the inspection errors shortages may sometimes occur in this paper we develop an economic order quantity model with imperfect quality items inspection errors shortage backordering and sales returns a closed form solution is obtained for the optimal order size the maximum shortage level and the optimal order reorder point if shortages are not allowed we adopt the order overlapping scheme proposed by maddah et al 2010 computers and industrial engineering 58 4 691 695 to develop an eoq model to prevent shortages during the screening process numerical examples show the impacts of the defective probability the inspection errors and the holding and backordering costs on the optimal solution

migration flows in commodity cycles assessing the role of migration policies this paper sheds light on the role of immigration policies in shaping immigration flows in responses to labor market changes using data from australia during the 2001 to 2015 commodity cycle as a quasi experiment we find that employer sponsored demand driven immigration varied in line with commodity prices with commodity intensive states witnessing stronger growth rates than remaining states over the resources boom period there is no evidence of any such patterns for points based supply driven immigrants moreover we do not find either employer sponsored or point based migration flows increase in non tradable sector in relative to tradable sector in the triple differences analysis with state industry level data these findings emphasize the importance of employer sponsored immigration in alleviating short term local labor shortages c 2020 elsevier b v all rights reserved

migration with endogenous moving costs we study a dynamic model of labor migration in which moving costs decrease with the number of migrants already settled in the destination this assumption is supported by sociological studies of migrant networks with endogenous moving costs migration occurs gradually over time once it starts it develops momentum and migratory flows may increase even as wage differentials narrow in addition migration tends to follow geographical channels and low moving cost individuals migrate first these patterns are consistent with historical evidence from the great black migration of 1915 1960 in the united states much of which cannot be reconciled with existing migration models excerpt

disaggregation and consolidation of imperfect quality shipments in an extended epq model abstract we consider a standard economic production quantity epq model due to manufacturing variability a fraction p of the produced inventory will have imperfect quality where p is a random variable with a known distribution we consider a 100 inspection policy and further assume that the inspection rate is larger than that of production thus all imperfect quality items will be detected by the end of the production cycle for such an augmented epq model we first derive the new optimal production quantity assuming that the imperfect quality items are salvaged once at the end of every production cycle then we extend this base model to allow for disaggregating the shipments of imperfect quality items during a single production run finally we consider aggregating or consolidating the shipments of imperfect items over multiple production runs under both scenarios we derive closed form expressions for both the economic production quantity and the batching policy and show that our desegregation consolidation schemes can lead to significant cost savings over the base model

eoq with a correlated binomial supply abstract this paper considers a variant of the economic order quantity eoq model under random supply a binomial supply model is adopted where every item received is of imperfect quality with the same probability we study the realistic case where the qualities of items in an order are correlated and draw useful insights the most interesting of which is that correlation decreases the order size several practical correlation patterns are investigated and discussed we also show that several commonly used models in the literature can be represented by an equivalent correlated binomial supply model

balanced budget redistribution as the outcome of political competition this paper models balanced budget redistribution between socio economic groups as the outcome of electoral competition between two political parties equilibrium is unique in the present model and a sufficient condition for existence is given requiring that there be enough stochastic heterogeneity with respect to party preferences in the electorate the validity of hotelling s principle of minimum differentiation and of director s law are examined under alternative hypotheses concerning administrative costs of redistributions and voter s possibilities both of abstaining from voting and of becoming campaign activists for one of the parties the policy strategy of expected plurality maximization is contrasted with the strategy of maximizing the probability of gaining a plurality incomes are fixed and known so lump sum taxation is feasible however constraints on tax transfer differentiation between individuals are permitted in the analysis

redistributive politics and economic efficiency the political process often compensates the losers from technical change or international competition in an economically inefficient way namely by subsidizing or protecting declining industries instead of encouraging the movement of resources to other more productive uses we find that a dynamic inconsistency in the game of redistributive politics contributes to this outcome to achieve economically efficient outcomes it is necessary that those making economically inefficient choices not be given offsetting transfers but the political process distributes income on the basis of political characteristics which are in general different from the economic characteristics that are rewarded by the market we identify circumstances in which the inefficient choosers have desirable political characteristics and are therefore immune from threats of having to face the economic consequences of their choices

the human capital stock a generalized approach this paper presents a new framework for human capital measurement the generalized framework can i substantially amplify the role of human capital in accounting for cross country income dierences and ii reconcile the existing con ict between regression and accounting evidence in assessing the wealth and poverty of nations one natural interpretation emphasizes dierences across economies in the acquisition of advanced knowledge by skilled workers

network effects and the dynamics of migration and inequality theory and evidence from mexico international migration is costly and initially only the middle class of the wealth distribution may have both the means and incentives to migrate which can increase inequality in the sending community however the migration networks formed lower the costs for future migrants which can in turn lower inequality this paper shows both theoretically and empirically that wealth has a nonlinear effect on migration and then examines the empirical evidence for an inverse u shaped relationship between emigration and inequality in rural sending communities in mexico after instrumenting we find that the overall impact of migration is to reduce inequality across communities with relatively high levels of past migration we also find some suggestive evidence for an inverse u shaped relationship among communities with a wider range of migration experiences

understanding different migrant selection patterns in rural and urban mexico abstract the productive characteristics of migrating individuals emigrant selection affect welfare the empirical estimation of the degree of selection suffers from a lack of complete and nationally representative data this paper uses a dataset that addresses both issues the enet mexican labor survey which identifies emigrants right before they leave and allows a direct comparison to non migrants this dataset presents a relevant dichotomy it shows negative selection for urban mexican emigrants to the united states for the period 2000 2004 together with positive selection in mexican emigration out of rural mexico to the united states in the same period three theories that could explain this dichotomy are tested whereas higher skill prices in mexico than in the us are enough to explain half of the negative selection result in urban mexico its combination with network effects and wealth constraints fully accounts for positive selection in rural mexico

can selective immigration policies reduce migrants quality destination countries can adopt selective immigration policies to improve migrants quality screening potential migrants on the basis of observable characteristics also influences their self selection on unobservables we propose a model that analyzes the effects of selective immigration policies on migrants quality measured by their wages at destination we show that the prevailing pattern of selection on unobservables influences the effect of an increase in selectivity which can reduce migrants quality when migrants are positively self selected on unobservables we also demonstrate that in this case the quality maximizing share of educated migrants declines with the scale of migration

immigrant selection in the oecd in this paper we examine the determinants of educational selectivity in immigration using immigrant stock data for 70 source countries and 21 oecd destination countries as observed in the year 2000 2001 we develop a variant of the roy model to estimate the determinants of educational selectivity two key findings emerge first the effect of the skill premium which is at the core of the roy model can be observed only after we take into account the poverty constraints operating in the source countries second cultural similarities colonial legacies and physical distance are often more important determinants of educational selectivity than wage incentives or selective immigration policy

international tax coordination regionalism versus globalism tax competition for mobile capital can undermine the attempts of governments to redistribute income from rich to poor i study whether international tax coordination can alleviate this problem using a general equilibrium model synthesizing recent contributions to the tax competition literature the model highlights the crucial distinction between global tax coordination and regional coordination with high capital mobility between the tax union and the rest of the world the welfare gain from regional capital income tax coordination is only a small fraction of the gain from global coordination even if the tax union is large relative to the world economy

economic and social class voting in a model of redistribution with social concerns we investigate how concerns about social status may affect individuals preferences for redistribution in our model agents are heterogeneous across two dimensions productivity and social class and an individual s social status is de ned as his relative standing in terms of a weighted average of these two components the weight on each component depends positively on its standard deviation redistribution thus simultaneously affects labor supply and the weights that determine social status as such taxation not only redistributes resources from the rich to the poor but also becomes a way of preserving or modifying social status thus individuals who have the same productivity but belong to different social classes support different tax rates we characterize the equilibrium of the political game as the solution of a system of non linear equations and identify the interclass coalition of voters who support the equilibrium tax rate

nonparametric regression techniques in economics this introduction to nonparametric regression emphasizes techniques that might be most accessible and useful to the applied economist the paper begins with a brief overview of the class of models under study and central theoretical issues such as the curse of dimensionality the bias variance trade off and rates of convergence the paper then focuses on kernel and nonparametric least squares estimation of the nonparametric regression model and optimal differencing estimation of the partial linear model constrained estimation and hypothesis testing is also discussed empirical examples include returns to scale in electricity distribution and hedonic pricing of housing attributes

a century of evolution from harris s basic lot size model survey and research agenda abstract determining the economic lot size has always represented one of the most important issues in production planning this problem has long attracted the attention of researchers and several models have been developed to meet requirements at minimum cost in this paper we explore and discuss the evolution of these models during one hundred years of history starting from the basic model developed by harris in 1913 up to today following harris s work a number of researchers have devised extensions that incorporate additional considerations the evolution of eoq theory strongly reflects the development of industrial systems over the past century here we outline all the research areas faced in the past by conducting a holistic analysis of 219 selected journal papers and trying to give a comprehensive view of past work on the eoq problem finally a new research agenda is proposed and discussed

lot sizing with a markov production process and imperfect items scrapped abstract this paper considers an inventory system within the economic order quantity eoq model framework under random supply the production process can go out of control with a constant probability and start producing imperfect quality items such a system has been studied in the literature under the assumption that defective items are reworked instantaneously and returned to inventory in some situations imperfect quality items are not necessarily defective and are removed from the inventory to be used elsewhere this paper develops two models where imperfect items are removed from inventory the first model finds the expected cost and optimal lot size assuming that imperfect quality items are removed from inventory at no cost the second model assumes that batches of imperfect quality are consolidated and shipped together due to economies of scale in shipping analytical and numerical results are developed for both models revealing several managerial insights

migration and employment after an economic shock regional characteristics and migration patterns this study addresses the migration dynamics of workers after their workplace has closed it analyses to what extent migration responses differ between regions with different characteristics for ind

the effects of party competition on budget outcomes empirical evidence from local governments in spain this paper investigates the link between local budget outcomes and the intensity of party competition measured as the margin of victory obtained by the incumbent in the previous local election i e the difference between the vote share and 50 two competing hypotheses are tested in the paper on the one hand the leviathan government hypothesis suggests that the lower the intensity of party competition is the greater is the increase in the size of the local public sector irrespective of the ideology of the party in power on the other hand the partisan government hypothesis suggests that the incumbent will find it easier to advance its platform when intensity of competition is low i e parties on the left right will increase decrease the size of the local public sector when the intensity of the challenge from the opposition is low these hypotheses are tested with information on spending own revenues and deficit for more than 500 spanish local governments over 8 years 1992 1999 and information on the results of two local electoral contests 1991 and 1995 the evidence favors the partisan hypothesis over the leviathan one we found that for left wing governments spending taxes and deficits increased as the electoral margin increases whereas for right wing governments a greater margin of victory led to reductions in all these variables

income maximization and the selection and sorting of international migrants abstract two prominent features of international labor movements are that the more educated are more likely to emigrate positive selection and more educated migrants are more likely to settle in destination countries with high rewards to skill positive sorting using data on emigrant stocks by schooling level and source country in oecd destinations we find that a simple model of income maximization can account for both phenomena results on selection show that migrants for a source destination pair are more educated relative to non migrants the larger is the absolute skill related difference in earnings between the destination country and the source results on sorting indicate that the relative stock of more educated migrants in a destination is increasing in the absolute earnings difference between high and low skilled workers we use our framework to compare alternative specifications of international migration estimate the magnitude of migration costs by source destination pair and assess the contribution of wage differences to how migrants sort themselves across destination countries

the political economy of intergovernmental grants evidence from a maturing democracy we evaluate the impact of political forces in the allocation of intergovernmental grants in portugal as it matured from a young to an established democracy using a large and unexplored dataset we show that political variables condition the granting system and that their importance changed over time while tactical manipulation in the distribution of grants among municipalities seems to exist only in the early years of democracy opportunistic effects are stronger in the latter years we argue that the latter effect is due to a change in the political environment and to the electorate s lack of information on intergovernmental grants

self selection and the earnings of immigrants this paper analyzes the way in which the earnings of the immigrant population may be expected to differ from the earnings of the native population because of the endogeneity of the decision to migrate the empirical study shows that differences in the u s earnings of immigrants with the same measured skills but from different home countries are attributable to variations in political and economic conditions in the countries of origin at the time of migration excerpt

ideology tactics and efficiency in redistributive politics we model the electoral politics of redistribution when voters and parties care about inequality in addition to their private concerns for consumption and votes respectively ideological concerns about income redistribution lead each party to adopt a general proportional income tax adjusted to appeal to the ideological leanings of high clout groups with disproportionately many swing voters which the parties also ply with pork barrel projects our results relate to director s law which says that redistributive politics favors middle classes at the expense of both rich and poor

an integrated production inventory model with imperfect production processes and weibull distribution deterioration under inflation abstract this study develops an integrated production and inventory model from the perspectives of both the manufacturer and the retailer the model assumes a varying rate of deterioration partial backordering inflation imperfect production processes and multiple deliveries the elapsed time until the production process shift is assumed to be arbitrarily distributed the discounted cash flow and classical optimization technique are used to derive the optimal solution a numerical example including the sensitivity analysis is given to validate the results of the production inventory model the integrated decision results in lower optimal joint cost compared with an independent decision by the manufacturer and the retailer

are immigrants favorably self selected one of the standard propositions in the migration literature is that migrants tend to be favorably self selected for labor market success that is economic migrants are described as tending on average to be more able ambitious aggressive entrepreneurial or otherwise more favorably selected than similar individuals who choose to remain in their place of origin in recent years there have been challenges to the general proposition of the favorable selectivity of migrants in addressing this issue this paper considers alternative specifications of the migration model that are relevant for the issue of migrant selectivity excerpt

seat vote curves loyalty effects and the provincial distribution of canadian government spending federal government spending in the canadian provinces for 1962 2002 is examined with emphasis on the role of seat vote elasticities in majoritarian electoral systems fixed effects regressions establish that per capita federal spending in a province increases with political competition as measured by provincial seat vote elasticities and with loyalty to the federal government as measured by the degree of provincial support for the federal government however too much loyalty can be counter productive because very loyal provinces are uncompetitive with low seat vote elasticities

an eoq model with backorders and rejection of defective supply batches abstract we consider a single echelon inventory installation under the classical eoq with backorders paradigm to study the effects of supply quality on cost performance previous research on imperfect supply quality has focused on variants of the proportional deterministic or random yield problem where supply batches are all accepted and then used after screening any defects in this paper we study an alternative setting where entire supply batches may be defective below quality standards and therefore rejected on arrival note that such supply flow disruptions are analogous to those considered within the economic order quantity with disruptions eoqd area of research we first present an exact model for the system expected cost and show its convexity optimal cost and respective values of the decision variables i e planned order quantity and backorders are then obtained in a closed form interestingly under perfect supply quality all expressions reduce to those of classical eoq analytical and computational results reveal the serious impact of inferior supply quality on system cost as well as the sensitivity of the system parameters

economic production quantity model for items with imperfect quality abstract the assumptions necessary to justify the use of economic production quantity epq eoq models are rarely met to provide mathematical models that more closely conform to actual inventories and respond to the factors that contribute to inventory costs the models must be extended or altered this paper hypothesizes a production inventory situation where items received or produced are not of perfect quality items of imperfect quality not necessarily defective could be used in another production inventory situation that is less restrictive process and acceptance control the electronics industry gives good examples of such situations this paper extends the traditional epq eoq model by accounting for imperfect quality items when using the epq eoq formulae this paper also considers the issue that poor quality items are sold as a single batch by the end of the 100 screening process a mathematical model is developed and numerical examples are provided to illustrate the solution procedure

economic order quantity for items with imperfect quality revisited abstract we rectify a flaw in an economic order quantity eoq model with unreliable supply characterized by a random fraction of imperfect quality items and a screening process developed by salameh and jaber 2000 economic production quantity model for items with imperfect quality international journal of production economics 64 1 3 59 64 this leads to simple expressions of the optimal order quantity and expected profit per unit time we then analyze the effect of screening speed and variability of the supply process on the order quantity and show that the order quantity in our model is larger than that of the classical eoq model when the variability of the yield rate is reasonably low in addition we extend the model by allowing for several batches of imperfect quality items to be consolidated and shipped in one lot this is likely to be useful when there are economies of scale in shipping of imperfect quality items finally we present numerical results to illustrate the application of the model and draw insights

economic production quantity model for items with imperfect quality subject to learning effects abstract salameh and jaber 2000 international journal of production economics 64 59 64 developed an inventory situation where items received are not of perfect quality defective and after 100 screening imperfect quality items are withdrawn from inventory and sold at a discounted price this paper extends the work of salameh and jaber by assuming the percentage defective per lot reduces according to a learning curve which was empirically validated by data from the automotive industry mathematical models are developed with numerical examples provided and discussed the developed model was compared with the model of salameh and jaber to emphasize the importance of learning

production and replacement policies for a deteriorating manufacturing system under random demand and quality abstract this work investigates the production planning of an unreliable deteriorating manufacturing system under uncertainties the effect of the deterioration phenomenon on the machine is mainly observed in its availability and the quality of the parts produced with the rates of failure and defectives increasing with the age of the machine the option to replace the machine should be considered to mitigate the effect of deterioration in order to ensure long term satisfaction of demand the objective of this paper is to find the production rate and the replacement policy that minimize the total discounted cost which includes inventory backlog production repair and replacement costs over an infinite planning horizon we formulate the stochastic control problem in the framework of a semi markov decision process to consider the machine s history the integration of random demand and quality behaviour led us to propose a new modeling approach by developing optimality conditions in terms of a second order approximation of hamilton jacobi bellman hjb equations numerical methods are used to obtain the optimal control policies finally a numerical example and a sensitivity analysis are presented in order to illustrate and confirm the structure of the optimal solution obtained

capital taxation under political constraints this paper studies optimal dynamic tax policy under the threat of political reform a policy will be reformed ex post if a large enough coalition of citizens supports reform thus sustainable policies are those that will continue to attract enough political support in the future we find that optimal marginal capital taxes are either progressive or u shaped so that savings are subsidized for the poor and or the middle class but are taxed for the rich u shaped capital taxes always emerge when individuals political behavior is purely determined by economic motives

partisan alignment effects on total factor productivity aray h partisan alignment effects on total factor productivity regional studies unlike the literature on political effects on real economy that suggests that partisan effects accrue through aggregate demand it is hypothesized that such effects could also accrue through aggregate supply using panel data for the spanish regions over the 1986 2010 period the main results are 1 partisan alignment effects only arise when central government enjoys a majority 2 there exist a positive contemporaneous effect and negative lagged effects and 3 in absolute value such effects vanish over time results are robust to different specifications and measures of total factor productivity tfp and methods of estimation

heaven s swing door endogenous skills migration networks and the effectiveness of quality selective immigration policies a growing number of oecd countries are leaning toward the adoption of selective immigration policies which are expected to raise the quality or education level of migrants this view neglects two important dynamic effects the role of migration networks which could reduce the quality of migrants and the responsiveness of education decisions to the prospect of migration we propose a model of self selection into migration with endogenous education choices which predicts that migration networks and the quality of migrants can be positively associated when destination countries adopt sufficiently selective immigration policies empirical evidence presented as background motivation suggests that this is indeed the case

clientelism and voting behavior evidence from a field experiment in benin the author conducted a field experiment in benin to investigate the impact of clientelism on voting behavior in collaboration with four political parties involved in the 2001 presidential elections clientelist and broad public policy platforms were designed and run in twenty randomly selected villages of an average of 756 registered voters using the survey data collected after the elections the author estimated the effect of each type of message by comparing voting behavior in the villages exposed to clientelism or public policy messages treatment groups with voting behavior in the other villages control groups the author found that clientelist messages have positive and significant effect in all regions and for all types of candidates the author also found that public policy messages have a positive and significant effect in the south but a negative and significant effect in the north in addition public policy messages seem to hurt incumbents as well as regional candidates finally the evidence indicates that female voters tend to have stronger preference for public policy platforms than male voters

networks in the modern economy mexican migrants in the u s labor market this paper attempts to identify job networks among mexican migrants in the u s labor market the empirical analysis uses data on migration patterns and labor market outcomes based on a sample of individuals belonging to multiple origin communities in mexico over a long period of time each community s network is measured by the proportion of the sampled individuals who are located at the destination the united states in any year we verify that the same individual is more likely to be employed and to hold a higher paying nonagricultural job when his network is exogenously larger by including individual fixed effects in the employment and occupation regressions and by using rainfall in the origin community as an instrument for the size of the network at the destination

do formula based intergovernmental transfer mechanisms eliminate politically motivated targeting evidence from ghana abstract various countries have adopted formulas for determining intergovernmental transfers as a strategy to limit the role of political considerations in resource allocation in this paper we investigate a formula based system of allocating resources from a central government to local governments to determine whether the political characteristics of recipient areas have any bearing on their allocation specifically we study the sharing of resources of the district assemblies common fund dacf in ghana amongst the country s district governments over the period 1994 to 2005 we find evidence that the mechanism does not eliminate politically motivated targeting of the grants per capita dacf grants were higher in districts where vote margins in the previous presidential election were lower suggesting that swing districts were targeted we find evidence that dacf formula indicators and their weighting were chosen and amended to produce politically desired patterns of transfers

economic ordering quantity models for items with imperfect quality abstract in this paper we first look at the issue of non shortages in models with proportional imperfect quality when the proportion of the imperfects is a random variable more specifically we revisit the papers of salameh and jaber int j prod econom 64 2000 59 and chan et al prod plann control 14 2003 588 and we point out that the sufficient conditions given in these papers to ensure that shortages will not occur may not really prevent their occurrence next considering the timing of withdrawing the imperfect quality items from stock we clarify a point not clearly stated in salameh and jaber int j prod econom 64 2000 59 and we extented this model to the case in which withdrawing takes place at the end of the planning horizon finally we establish that the objective of maximizing the mean average profit which was set in salameh and jaber int j prod econom 64 2000 59 is superfluous and the results given there can be obtained by ignoring the revenue issues assumed in the model and minimizing directly the mean average cost

international migration self selection and the distribution of wages evidence from mexico and the united states we use the 1990 and 2000 mexican and u s population censuses to test borjas s negative selection hypothesis that the less skilled are those most likely to migrate from countries with high skill premia earnings inequality to countries with low skill premia earnings inequality we find that mexican immigrants in the united states are more educated than nonmigrants in mexico and were mexican immigrants to be paid according to current skill prices in mexico they would be concentrated in the middle of mexico s wage distribution these results are inconsistent with the negative selection hypothesis and instead suggest that there is intermediate selection of immigrants from mexico

economic order quantity model for items with imperfect quality with learning in inspection abstract the economic order quantity eoq model is the simplest and earliest inventory model in the literature its simple mathematics is attributed to its assumptions which are rarely met salameh and jaber 2000 economic production quantity model for items with imperfect quality int j prod econ 64 59 64 addressed one of these assumptions that items received or produced are not of perfect quality this paper extends salameh and jaber s work for the case where there is learning in inspection the model is realistic in that it considers situations of lost sales and backorders mathematical models are developed with numerical examples provided and results discussed for the cases of i partial transfer of learning ii total transfer of learning and iii no transfer of learning