household choices and child development the growth in labor market participation among women with young children has raised concerns about the potential negative impact of the mother s absence from home on child outcomes recent data show that mother s time spent with children has declined in the last decade while the indicators of children s cognitive and noncognitive outcomes have worsened the objective of our research is to estimate a model of the cognitive development process of children nested within an otherwise standard model of household life cycle behavior the model generates endogenous dynamic interrelationships between the child quality and employment processes in the household which are found to be consistent with patterns observed in the data the estimated model is used to explore the eects of schooling subsidies and employment restrictions on household welfare and child development

the demand for and impact of learning hiv status this paper evaluates an experiment in which individuals in rural malawi were randomly assigned monetary incentives to learn their hiv results after being tested distance to the hiv results centers was also randomly assigned without any incentive 34 percent of the participants learned their hiv results however even the smallest incentive doubled that share using the randomly assigned incentives and distance from results centers as instruments for the knowledge of hiv status sexually active hiv positive individuals who learned their results are three times more likely to purchase condoms two months later than sexually active hiv positive individuals who did not learn their results however hiv positive individuals who learned their results purchase only two additional condoms than those who did not there is no significant effect of learning hiv negative status on the purchase of condoms

the perceived returns to education and the demand for schooling economists emphasize the link between market returns to education and investments in schooling though many studies estimate these returns with earnings data it is the perceived returns that affect schooling decisions and these perceptions may be inaccurate using survey data for eighth grade boys in the dominican republic we find that the perceived returns to secondary school are extremely low despite high measured returns students at randomly selected schools given information on the higher measured returns completed on average 0 20 0 35 more years of school over the next four years than those who were not

introducing household production in collective models of labor supply in a recent paper chiappori 1992 i proposed a model of labor supply based on a collective representation of household behavior in this framework each household member is characterized by his or her own utility function and decisions are only assumed to result in pareto efficient outcomes i showed that these simple assumptions were sufficient to i generate testable restrictions on labor supply functions and ii recover individual preferences and the outcome of the decision process from observed behavior for the sake of simplicity the results were derived in the simplest possible case namely a static labor supply model with private consumptions such a framework was appropriate only for the purpose of the paper that is a preliminary exploration of the properties of collective models of labor supply the next step is to evaluate the robustness of the results to various extensions of the basic model this opens a general research program and generates a wide range of particular problems that it is hoped will be considered in the future among the most serious shortcomings of the 1992 model is the absence of household production as in most labor supply models agents were assumed to divide their time between market activities and leisure as apps and rees 1997 in this issue very rightly point out in their comment the absence of domestic production is far from innocuous as soon as welfare issues are considered for instance a low level of market labor supply will automatically be interpreted as a large consumption of leisure whereas it may in fact reflect the specialization of one of the members in domestic

simultaneous clearing of energy and reserves in multi area markets under mixed pricing rules the integration of the spot electricity markets in europe shall lead to multi area power exchanges that will substitute the local markets in such scheme market prices are affected by physical e g network constraints yet they should sometimes follow regulatory policy rules which do not necessarily reflect or depend on physical characteristics in some cases complex pricing rules should be implemented which impose price discrimination for supply and demand entities within the same area the methodology presented in this paper enables the balancing of supply and demand in a multi area market considering energy and reserve bids under complex pricing rules which mix energy and reserve prices a demand bid corresponds to the whole cost a demand entity is willing to pay for its participation in the energy market including the cost for the procurement of the necessary reserves the approach attains price integration of energy and reserves markets simultaneous settlement of energy and reserves and significant decrease of the payments through the uplift accounts the main principle is the formulation of a mixed complementarity problem for the system equilibrium conditions in which supply and demand are associated to explicitly or implicitly defined prices which may be different even in the same zone

market clearing with stochastic security part i formulation the first of this two paper series formulates a stochastic security constrained multi period electricity market clearing problem with unit commitment the stochastic security criterion accounts for a pre selected set of random generator and line outages with known historical failure rates and involuntary load shedding as optimization variables unlike the classical deterministic reserve constrained unit commitment here the reserve services are determined by economically penalizing the operation of the market by the expected load not served the proposed formulation is a stochastic programming problem that optimizes concurrently with the pre contingency social welfare the expected operating costs associated with the deployment of the reserves following the contingencies this stochastic programming formulation is solved in the second companion paper using mixed integer linear programming methods two cases are presented a small transmission constrained three bus network scheduled over a horizon of four hours and the ieee reliability test system scheduled over 24 h the impact on the resulting generation and reserve schedules of transmission constraints and generation ramp limits of demand side reserve of the value of load not served and of the constitution of the pre selected set of contingencies are assessed

the importance of being informed experimental evidence on demand for environmental quality abstract to what extent does information affect the demand for environmental quality a randomly selected group of households in an indian city were informed whether or not their drinking water had tested positive for fecal contamination using a simple inexpensive test kit households initially not purifying their water and told that their drinking water was possibly contaminated were 11 percentage points more likely to begin some form of home purification in the next eight weeks than households that received no information they spent 7 24 at ppp more on purification than control households by way of comparison an additional year of schooling of the most educated male in the household is associated with a 3 percentage point rise in the probability of initial purification while a standard deviation increase in the wealth index is associated with a 12 percentage point rise in this probability and an 11 75 rise in expenditure initially purifying households that received a no contamination result did not react by reducing purification these results suggest that estimates of the demand for environment quality that assume full information may significantly under estimate it

ex ante and ex post labor supply response to risk in a low income area abstract this paper tests for ex ante and ex post labor supply responses to weather risk for rural indian farm households the analysis uses panel data on 2115 households spanning 13 states in rural india merged with a 22 year series of district level rainfall data ex ante households facing riskier distributions of rainfall are more likely to participate in the labor market ex post unexpectedly bad weather and low rainfall increase labor force participation

the effect of female education on fertility and infant health evidence from school entry policies using exact date of birth this paper uses age at school entry policies to identify the effect of female education on fertility and infant health we focus on sharp contrasts in schooling fertility and infant health between women born just before and after the school entry date school entry policies affect female education and the quality of a woman s mate and have generally small but possibly heterogeneous effects on fertility and infant health we argue that school entry policies manipulate primarily the education of young women at risk of dropping out of school

european electricity market integration with mixed market designs part ii solution algorithm and case studies this paper presents the solution algorithm and test results of the market splitting approach proposed in the first part of this two paper series for the clearing of the forthcoming internal electricity market the market splitting approach is implemented in a europe wide level indicatively defining three power pools and 22 power exchanges comprising 42 bidding areas in total with each local national market respecting the standard market regulatory framework of power pools and power exchanges pxs the performance and computational requirements of this implementation is presented the model is tested in terms of problem solvability to its limits considering a day ahead market clearing time threshold equal to one hour the results demonstrate that a viable solution to the clearing of the internal electricity market can be attained with the current state of the art of computers processing power further discussion is made concerning the viability of the proposed approach and other harmonization issues that should be considered for successful market integration

nutrition information and household behavior experimental evidence from malawi incorrect knowledge of the health production function may lead to inefficient household choices and thereby to the production of suboptimal levels of health this paper studies the effects of a randomized intervention in rural malawi that over a six month period provided mothers of young infants with information on child nutrition without supplying any monetary or in kind resources a simple model first investigates theoretically how nutrition and other household choices including labor supply may change in response to the improved nutrition knowledge observed in the intervention areas we then show empirically that the intervention improved child nutrition household food consumption and consequently health we find evidence that labor supply increased which might have contributed to partially fund the increase in food consumption this paper is the first to study whether non health choices particularly parental labor supply might be affected by parents knowledge of the child health production function

market clearing with stochastic security part ii case studies this paper analyzes the market clearing formulation with stochastic security developed in its companion paper through two case studies solved using mixed integer linear programming techniques the generation and reserve schedules as well as the nodal prices of energy and security are assessed under various conditions such as a line flow limits b when nonspinning reserve is excluded from the formulation c demand side valuation of energy not served d generator ramping limits and e the set of pre selected contingencies

an optimization model for the electricity market clearing problem with uniform purchase price and zonal selling prices electricity markets can be designed in different ways one rule that is sometimes enforced is the uniform purchase price under this pricing method all the consumers pay the same price regardless of the zone they belong to by contrast each producer receives its zonal price this asymmetry in the price paid and received makes the clearing process not easily treatable through standard optimization techniques within the framework of marginal pricing this paper shows how it is possible to formulate the market clearing problem with uniform purchase price and zonal selling prices as a computationally tractable mixed integer linear programming problem the proposed approach is tested using real data from the italian day ahead market which is actually based on the aforementioned rule

balancing supply and demand under mixed pricing rules in multi area electricity markets market clearing has always been an issue of great interest and research as liberalized electricity markets evolved over time in many countries as trading in electricity evolves rapidly multi area power exchanges appear to substitute the local markets the tie lines constitute a significant parameter in multi area power exchanges since congestion leads to price differentiation prices are affected by physical e g network constraints yet they should sometimes follow regulatory policy rules which do not necessarily reflect or depend on physical characteristics until now all approaches in clearing a multi area power dispatch or a multi area market are based on a zonal or nodal pricing model which is applied uniformly to both production and demand within the same zone or at each node these approaches are not able to deal with complex pricing rules which impose price discrimination for supply or demand entities within the same area this paper presents a mathematical approach for the solution of a multi area dispatch in which production and demand of the same area may be cleared in different prices the main principle is the formulation of a mixed complementarity problem for the system equilibrium conditions in which supply and demand are associated to explicitly or implicitly defined prices illustrative implementations and test results for a simple five zone system and the 73 bus ieee rts 96 are presented

deliverable robust ramping products in real time markets the increasing penetration of variable energy resources has led to more uncertainties in power systems flexible ramping products frp have been adopted by several electricity markets to manage the uncertainties we reveal that neglected line congestion for frp may not only cause infeasibility but also result in a failure of cost recovery to address the deliverability issues on frp this paper proposes a new concept deliverable robust ramping products drrp in real time markets the drrp includes generation ramping reserve and generation capacity reserve the drrp is deliverable and immunized against any predefined uncertainty it also fully addresses the bid cost recovery issue caused by the line congestion in existing frps the prices of drrp are derived within the affine adjustable robust optimization aaro framework these prices can be used to identify valuable reserves among available reserves and quantify the values of flexible resources that provide reserves this paper also proposes a general approach to obtaining the time decoupled prices for drrp and generation which can be used for the market settlement of the first interval only in real time markets simulations on a 3 bus system and the ieee 118 bus system are performed to illustrate the concept of drrp and the advantages of drrp compared to existing frp

robust security constrained unit commitment and dispatch with recourse cost requirement with increasing renewable energy resources price sensitive loads and electric vehicle charging stations in the power grid uncertainties on both power generation and consumption sides become critical factors in the security constrained unit commitment scuc problem recently worst scenario based robust optimization approaches are employed to consider uncertainties this paper proposes a non conservative robust scuc model and an effective solution approach the contributions of this paper are three fold first the commitment and dispatch solution obtained in this paper can be directly used in day ahead market as it overcomes two issues conservativeness and absence of robust dispatch which are the two largest obstacles to applying robust scuc in real markets secondly a new concept recourse cost requirement similar to reserve requirement is proposed to define the upper bound of re dispatch cost when uncertainties are revealed thirdly a novel decomposition approach is proposed to effectively address the well known computational challenge in robust approaches simulation results on the ieee 118 bus system validate the effectiveness of the proposed novel model and solution approach

multi area power generation dispatch in competitive markets in competitive electric energy markets the power generation dispatch optimization is one of the most important missions among generation companies how to respond to the markets dispatch their units and maximize profits this paper proposes an approach to incorporate power contracts which include call and put options forward contracts and reliability must run contracts into multi area unit commitment and economic dispatch solutions the proposed solution algorithm is based on adaptive lagrangian relaxation unit decommitment and lambda iteration methods the problem formulation consists of three stages 1 the incorporation of the power contracts 2 the multi area unit commitment and 3 the multi area economic dispatch the proposed algorithm has been successfully implemented and its testing results on modified ieee test cases are promising

group size and the efficiency of informal risk sharing this paper seeks to understand and test empirically the relationship between group size and informal risk sharing models of informal risk sharing with limited commitment and grim trigger punishments upon deviation imply that larger groups provide better insurance however when subgroups of households can credibly deviate so that sustainable informal arrangements ought to be coalition proof the relationship between group size and the amount of insurance is unclear building on genicot and ray 2003 we show that this relationship is theoretically ambiguous we then investigate it empirically using data on the size of the sibships of the household head and spouse in rural malawi to identify the relevant potential risk sharing group we exploit a social norm among the main ethnic group in our sample that the wife s brothers play a key role in ensuring her household s wellbeing we find that households where the wife has many brothers are poorly insured against crop loss events we fail to uncover a similar relationship for the wife s sisters ruling out that our findings are driven by wives with many siblings e g brothers simply having poorer extended family networks a simple calibration exercise indicates that the threat of coalitional deviations can explain our empirical findings

connecting the intraday energy and reserve markets by an optimal redispatch electricity markets based on simple bids provide a very high degree of transparency and simplicity however simple bids fail to capture many well known characteristics of generating units and therefore the responsibility for obtaining feasible schedules is transferred to market participants the purpose of this paper is to help the generating utility to automatically analyze the last energy program cleared in the market and in case this program is technically unfeasible to provide an alternative schedule by re dispatching the generating units this is achieved by formulating an optimization problem where the objective is to find the cheapest and feasible instantaneous power trajectory of each generator trying to minimize the differences between its hourly average values and the last energy program as the objectives of the utility can vary during the day three different models are presented two of them are formulated as a joint energy and reserve dispatch in order to take into account possible commitments acquired in the ancillary services market of agc regulation in this sense a novel approach for considering discontinuous ancillary regulation curves is proposed some numerical examples are included to illustrate the essential features of the models

mother s education and the intergenerational transmission of human capital evidence from college openings we examine the effect of maternal education on birth outcomes using vital statistics natality data from 1970 to 1999 we also assess the importance of four channels through which maternal education may improve birth outcomes use of prenatal care smoking marriage and fertility in an effort to account for the endogeneity of education attainment we use data about the availability of colleges in the womans country in her 17th year as an instrument for maternal education we find that higher maternal education improves infant health as measured by birth weight and gestational age it also increases the probability that a new mother is married reduces parity increases use of prenatal care and reduces smoking suggesting that may be important pathways for the ultimate effect on health our results add to the growing body of literature which suggests that estimates of the returns to education which focus only on increases in wages understate the total return

weather risk wages in kind and the off farm labor supply of agricultural households in a developing country this article investigates the effects of weather risk on the off farm labor supply of agricultural households in a developing country distinguishing different types of off farm labor markets a multivariate two limit tobit model is applied to data from india the regression results show that the share of the off farm labor supply increases with weather risk the increase is much larger in the case of nonagricultural work than in the case of agricultural wage work and the increase is much larger in the case of agricultural wages paid in kind than in the cash wage case suggesting farmers considerations of food security copyright 2007 oxford university press

fertilizer use risk and off farm labor markets in the semi arid tropics of india a two period model is developed in which a risk averse farmer uses off farm labor to smooth consumption leading to greater use of fertilizer fertilizer demand is shown to increase with the depth of the off farm labor market controlling for exogenous weather risk farmers use more fertilizer the lower the unemployment rate and the higher the share of nonagricultural work in total off farm labor the results suggest that off farm labor markets and own farm production may be complementary in risky production environments so that policies which promote the depth of the off farm labor market in low income areas may also bolster farm productivity copyright 2003 oxford university press

early childhood nutrition and academic achievement a longitudinal analysis abstract many policymakers propose early childhood nutrition programs as a way to increase students academic achievement this paper investigates the nutrition learning nexus using a unique longitudinal data set that follows a large sample of filipino children from birth until the end of their primary education we find that better nourished children perform significantly better in school partly because they enter school earlier and thus have more time to learn but mostly because of greater learning productivity per year of schooling our cost benefit analysis suggests that a dollar invested in an early childhood nutrition program in a developing country could potentially return at least three dollars worth of gains in academic achievement and perhaps much more

the illusion of sustainability this brief summarizes the results of a gender impact evaluation study entitled the illusion of sustainability conducted during the time period 1998 to 2001 in kenya the study observed that deworming is a public good since much of its social benefit comes through reduced disease transmission people were less likely to take deworming if their direct first order or indirect second order social contacts were exposed to deworming the introduction of a small fee for deworming drugs led to an 80 percent reduction in treatment rates take up was not sensitive to the exact price level suggesting that it is particularly counter productive to charge small positive prices for the treatment of infectious diseases an intensive school health education had no impact on worm prevention funding for the study derived from world bank nih fogarty international center berkeley center for health research

infant health and longevity evidence from a historical intervention in sweden this paper investigates the potential of an infant intervention to improve life expectancy contributing to emerging interest in the early life origins of chronic disease we track individuals from birth to death and are able to identify age and cause of death the intervention was pioneered in sweden in 1931 1933 and appears to have been pivotal in the emergence of universal infant care programmes in the scandinavian countries during the creation of the welfare state it provided information and support to mothers with an emphasis on nutrition and sanitation while monitoring infant care through home visits and clinics we estimate that the average duration of programme exposure in infancy led to a 1 56 point decline in the risk of infant death 24 of baseline risk and a 2 56 point decline in the risk of dying by age 75 7 0 of baseline risk and these impacts are much larger for children born out of wedlock intervention led declines in the risk of dying after the age of 50 are dominated by reductions in cancer and cardiovascular mortality we find no evidence of selective utilisation and the estimates are similar when we exploit within mother variation in outcomes less

pricing energy and ancillary services in integrated market systems by an optimal power flow a detailed ac opf based formulation for procuring pricing and settling energy and ancillary service in simultaneous auctions by integrated market systems is presented the paper provides clear definitions of locational marginal prices for energy and ancillary service marginal prices in terms of lagrange multipliers the characteristics of the prices are analyzed especially when economic substitution among ancillary services is required the paper also evaluates the conditions under which opportunity costs are incurred to units that provide ancillary services it is particularly shown that the intuitive belief that the provision of regulation down service does not incur opportunity cost to the provider in general is not true

is the wto mystery really solved the wto s impact on bilateral trade remains puzzling due in part to previous studies failure to simultaneously address three issues inclusion of zero trade proper controls for multilateral resistance and proper membership definition addressing all fails to suggest a positive effect

security constrained unit commitment with ac constraints in a restructured power market the independent system operator iso executes the security constrained unit commitment scuc program to plan a secure and economical hourly generation schedule for the day ahead market this paper introduces an efficient scuc approach with ac constraints that obtains the minimum system operating cost while maintaining the security of power systems the proposed approach applies the benders decomposition for separating the unit commitment uc in the master problem from the network security check in subproblems the master problem applies the augmented lagrangian relaxation lr method and dynamic programming dp to solve uc the subproblem checks ac network security constraints for the uc solution to determine whether a converged and secure ac power flow can be obtained if any network violations arise corresponding benders cuts will be formed and added to the master problem for solving the next iteration of uc the iterative process will continue until ac violations are eliminated and a converged optimal solution is found in this paper a six bus system and the ieee 118 bus system with 54 units are analyzed to exhibit the effectiveness of the proposed approach

economic conditions early in life and individual mortality this paper analyzes the effect of economic conditions early in life on the individual mortality rate later in life using business cycle conditions early in life as an exogenous indicator we have individual data records from dutch registers of birth marriage and death certificates covering an observation window of unprecedented size 1812 2000 these are merged with historical data on macro economic and health indicators we correct for secular changes over time and other mortality determinants we nonparametrically compare those born in a recession to those born in the preceding boom and we estimate duration models where the individual s mortality rate depends on current conditions conditions early in life age individual characteristics including individual socio economic indicators and interaction terms the results indicate a significant negative effect of economic conditions early in life on individual mortality rates at all ages

the oregon health insurance experiment evidence from the first year in 2008 a group of uninsured low income adults in oregon was selected by lottery to be given the chance to apply for medicaid this lottery provides an opportunity to gauge the effects of expanding access to public health insurance on the health care use financial strain and health of low income adults using a randomized controlled design in the year after random assignment the treatment group selected by the lottery was about 25 percentage points more likely to have insurance than the control group that was not selected we find that in this first year the treatment group had substantively and statistically significantly higher health care utilization including primary and preventive care as well as hospitalizations lower out of pocket medical expenditures and medical debt including fewer bills sent to collection and better self reported physical and mental health than the control group

do we really know that the wto increases trade comment in a recent article in the american economic review andrew k rose 2004 finds that countries belonging to the general agreement on tariffs and trade gatt and its successor the world trade organization wto did not trade more than countries that abstained from membership a vast literature on the gatt and the wto presupposes that these organizations were important but until rose there were few systematic efforts to test the assumption that membership increased trade rose s contribution is striking because he assembles a large dataset performs a myriad of analyses and uncovers scant evidence that the gatt and the wto had any impact rose describes his negative findings as an interesting mystery 112 the solution to this mystery lies in understanding who actually participated in the gatt we show that rose has overlooked a large proportion of countries to which the agreement applied and mistakenly classified them as nonparticipants when in fact they had rights and obligations under the agreement this causes a downward bias in his estimates of the gatt s effect on trade because his gravity regressions

the emperor has no clothes the limits of opec in the global oil market most scholars and policymakers believe opec can and does influence the price of oil by acting as a cartel this paper argues that most of the conventional wisdom about opec is wrong opec rarely if ever influences the oil production rate in its member states further opec has almost no lasting impact on world prices except under rare conditions there was one occasion on which opec did have a significant impact on world oil prices namely the 1973 oil crisis but opec s role in the event has been greatly misunderstood the circumstances of the crisis were highly exceptional making it unlikely that the organization could ever have a similar impact on world oil prices again this paper seeks to correct the misunderstanding about opec s role and replace it with a better understanding of the organization i argue that opec is dysfunctional as a cartel as it has little or no causal impact on its members choices about production levels or investment in production capacity opec s role is obscured in part by the complexity of the world oil market and in part by misdirection by policymakers especially within opec many scholars especially economists have argued that opec should be understood as a cartel designed to solve a prisoner s dilemma pd coordination game yet opec s persistence is better understood as a widespread failure to update beliefs about the organization a failure that is driven by information asymmetry and politics the fact that such a widespread belief about the world s most important commodity market could be wrong can help us better understand international regimes

the determinants of human capital formation during the early years of life theory measurement and policies in this paper i discuss a research agenda on the study of human capital accumulation in the early years with a particular focus on developing countries i discuss several methodological issues from the use of structural models to the importance of measurement and the development of new measurement tools i present a conceptual framework that can be used to frame the study of human capital accumulation and view the current challenges and gaps in knowledge within such an organizing structure i provide an example of the use of such a framework to interpret the evidence on the impacts of an early years intervention based on randomized controlled trial

utilization of real time balancing market for transmission system control under uncertainty an algorithm facilitating automated purchase of energy on real time balancing market is proposed in this paper the main inputs of the algorithm are a prediction of the area control error its uncertainty in the form of a standard deviation and a set of previously procured ancillary services contracted power reserves available for power balance control the algorithm evaluates all possible power balance scenarios for the closest hour in a probabilistic manner and gives a cost optimal recommendation for the real time balancing market demand a case study on realistic data for the czech republic control area was performed by simulation of the power balance control with a monte carlo simulator of the czech transmission system the results showed potential for savings on the regulation energy costs

energy and reserve dispatch in a multi zone electricity market competitive bidding for ancillary services a s in addition to bidding for energy is increasingly recognized as an important part of electricity markets in this paper an lp based approach is presented for solving the multi product i e energy and a s products multi zone area physical market dispatch problem the approach can explicitly represent various constraints such as reserve requirement constraints network security limits and sharing of constrained resource capacity e g maximum unit generation between energy and reserve the joint dispatch method which dispatches energy and reserve market concurrently is extended to allow inter zonal reserve trading in a multi zone competitive pool numerical examples are included to demonstrate the salient characteristics of the joint dispatch solution

health nutrition and economic development the relationship between health and economic development is explored focusing on nutrition based health indicators the spotlight is placed on the inter related feedbacks between the influence of health on productivity on one hand and the influence of income on health status on the other disentangling causality in these relationships has preoccupied much of the literature we evaluate different empirical strategies that have been adopted and assess the results there is now a body of evidence based on careful empirical studies that demonstrates a causal relationship between health and labor productivity there is also evidence that at least among the very poor additional income is spent on improved nutrition there are two issues that have received little attention although we argue they are likely to be very important first measurement of health is discussed in detail evidence is presented on how taking into account differences in the extent of measurement error is critical for interpreting the impact of health on wages the same theme emerges in studies of the effect of income on health specifically calorie intake the key role of non linearities in these relationships is highlighted and we demonstrate that a good deal of the variation in estimates of income elasticities of demand for calories can be ascribed to the role of measurement and functional form authors

smoothing consumption by smoothing income hours of work responses to idiosyncratic agricultural shocks in rural india while research has demonstrated that farm households in developing economies are able to protect consumption from idiosyncratic crop shocks little evidence shows how this is achieved this paper examines the extent to which labor markets allow households to shift labor from farm to off farm employment and the extent to which such a shift explains the observed lack of correlation between consumption and idiosyncratic crop shocks the empirical analysis uses a novel measure of the idiosyncratic crop income shock which utilizes information on start of season cropping choices to more accurately estimate household expectations of weather

do we really know that the wto increases trade reply michael tomz judith l goldstein and doug las rivers 1hereafter tgr2 argue that the general agreement on tariffs and trade gatt and its successor the world trade organization 1wto had a substantial positive effect on trade their paper is a critique of my article do we really know that the wto increases trade which appeared in this review 2004a among other things i used a bilateral gravity model of trade and showed that dummy variables for member ship by either one or two countries in the gatt had only small effects on trade in essence tgr point out that a lot of countries were not formal members of the gatt but still participated in it as colonies or de facto or provisional members tgr argue that if one includes these other types of more informal participation one gets large positive effects for what it s worth i stated in my original article that de jure accession to the gatt need not be the same as de facto accession but i wasn t able to quantify it and encouraged others to do so tgr did precisely that at the cost of much tedious archival work i applaud them for it and will certainly not question its accuracy i also like their methodological strategy which is to follow my empirical framework closely and rely mostly on simply adding informal partici pation to formal gatt membership tgr cite my work selectively but extensively it s a clean and effective way to proceed i like their paper and have learned a lot by reading it and thinking about the issues it raised all who are interested in the topic of the impact of the multilateral system on trade should take it seriously still i have concerns about the mean ing plausibility and robustness of their results do we really know that the wto increases trade reply

free distribution or cost sharing evidence from a randomized malaria prevention experiment author s cohen jessica dupas pascaline abstract it is often argued that cost sharing charging a subsidized positive price for a health product is necessary to avoid wasting resources on those who will not use or do not need the product we explore this argument through a field experiment in kenya in which we randomized the price at which prenatal clinics could sell long lasting anti malarial insecticide treated nets itns to pregnant women we find no evidence that costsharing reduces wastage on those that will not use the product women who received free itns are not less likely to use them than those who paid subsidized positive prices we also find no evidence that costsharing induces selection of women who need the net more those who pay higher prices appear no sicker than the average prenatal client in the area in terms of measured anemia an important indicator of malaria cost sharing does however considerably dampen demand we find that uptake drops by 75 percent when the price of itns increases from zero to 0 75 i e from 100 to 87 5 percent subsidy the price at which itns are currently sold to pregnant women in kenya we combine our estimates in a cost effectiveness analysis of itn prices on child mortality that incorporates both private and social returns to itn usage overall our results suggest that free distribution of itns could save many more lives than cost sharing programs have achieved so far and given the large positive externality associated with widespread usage of itns it would likely do so at a lesser cost per life saved

estimating a household production function heterogeneity the demand for health inputs and their effects on birth weight the household production literature emphasizes that technical or biological processes condition input selection by households in their production activities along with prices and income exogenous variations in health to the extent that they are perceived by individuals heterogeneity lead to correlations between inputs and health outcomes that cannot be used to derive causal conclusions therefore estimates of health technology must be obtained from a behavioral model in which health inputs are themselves choices consistent estimates are reported of the effect of endogenous inputs such as medical care smoking and fertility on birth weight and fetal growth in the presence of health heterogeneity

the divergent effects of joining international organizations trade gains and the rigors of wto accession governments have joined the world trade organization wto in vastly different ways some have taken mere days to join without undertaking any trade liberalization while others have taken more than a decade and been forced to undergo significant liberalization we argue that the more rigorous a state s accession to an international organization io and thus the greater policy change required to join the greater the benefits it will receive from membership in the organization in the trade context states facing greater scrutiny from the wto and thus engaging in greater trade liberalization as part of the wto accession process should experience greater trade on joining compared to those who face little scrutiny and engage in little if any liberalization we develop a three part classification of wto members based on type of accession early automatic and rigorous and then compile detailed original data on the accession experiences of each relevant state including length of time number of veto players rounds of questions and tariff and nontariff commitments results of exhaustive quantitative tests on all countries from 1950 to 2006 which are robust to estimator sample period and model specification choices consistently demonstrate that those who engage in the greatest amount of accession driven liberalization experience the greatest trade increases from wto membership particularly in the years right after joining in contrast those who do little or nothing to join do not see any trade gains from being a wto member these findings reconcile previous findings on the effects of wto membership on trade highlight the causal importance of io accession and illuminate the conditions under which ios will have beneficial effects for member states

credit market consequences of improved personal identification field experimental evidence from malawi we implemented a randomized field experiment in malawi examining borrower responses to being fingerprinted when applying for loans this intervention improved the lender s ability to implement dynamic repayment incentives allowing it to withhold future loans from past defaulters while rewarding good borrowers with better loan terms as predicted by a simple model fingerprinting led to substantially higher repayment rates for borrowers with the highest ex ante default risk but had no effect for the rest of the borrowers we provide unique evidence that this improvement in repayment rates is accompanied by behaviors consistent with less adverse selection and lower moral hazard jel d14 d82 g21 o12 o16

collective labour supply with children we extend the collective model of household behavior to allow for the existence of public consumption we show how this model allows the analysis of welfare consequences of policies aimed at changing the distribution of power within the household our setting provides a conceptual framework for addressing issues linked to the targeting of specific benefits or taxes we also show that the observation of the labor supplies and the household demand for the public good allow one to identify individual welfare and the decision process this requires either a separability assumption or the presence of a distribution factor

an analysis of sample attrition in panel data the michigan panel study of income dynamics by 1989 the michigan panel study on income dynamics psid had experienced approximately 50 percent sample loss from cumulative attrition from its initial 1968 membership we study the effect of this attrition on the unconditional distributions of several socioeconomic variables and on the estimates of several sets of regression coefficients we provide a statistical framework for conducting tests for attrition bias that draws a sharp distinction between selection on unobservables and on observables and that shows that weighted least squares can generate consistent parameter estimates when selection is based on observables even when they are endogenous our empirical analysis shows that attrition is highly selective and is concentrated among lower socioeconomic status individuals we also show that attrition is concentrated among those with more unstable earnings marriage and migration histories nevertheless we find that these variables explain very little of the attrition in the sample and that the selection that occurs is moderated by regression to the mean effects from selection on transitory components that fade over time consequently despite the large amount of attrition we find no strong evidence that attrition has seriously distorted the representativeness of the psid through 1989 and considerable evidence that its cross sectional representativeness has remained roughly intact

cluster sample methods in applied econometrics inference methods that recognize the clustering of individual observations have been available for more than 25 years brent moulton 1990 caught the attention of economists when he demonstrated the serious biases that can result in estimating the effects of aggregate explanatory variables on individual specific response variables the source of the downward bias in the usual ordinary least squares ols standard errors is the presence of an unobserved state level effect in the error term more recently john pepper 2002 showed how accounting for multi level clustering can have dramatic effects on t statistics while adjusting for clustering is much more common than it was 10 years ago inference methods robust to cluster correlation are not used routinely across all relevant settings in this paper i provide an overview of applications of cluster sample methods both to cluster samples and to panel data sets

security constrained unit commitment for simultaneous clearing of energy and ancillary services markets this paper introduces a security constrained unit commitment scuc model with emphases on the simultaneous optimization of energy and ancillary services markets benders decomposition is used to decouple the scuc into a unit commitment uc master problem and hourly network security checking subproblems lagrangian relaxation is used to decouple the uc problem into individual single unit commitment problems dynamic programming is used to find the optimal commitment decision a simultaneous marginal curve algorithm is proposed to find the optimal values of energy and ancillary services a six bus system with three units and the ieee 118 bus system with 54 units are analyzed to illustrate the proposed model

agricultural trade and the gatt wto does membership make a difference recent empirical studies have estimated the trade flow effect of membership in the world trade organization wto and its predecessor the general agreement on tariffs and trade gatt one important although largely untested conclusion from this literature is that the gatt wto works well if we ignore trade in agriculture one of the institutions seemingly apparent failures this article investigates this conclusion using a large panel of agricultural and non agricultural trade flows the results are impressive the multilateral institution has delivered significant positive effects on members agricultural trade despite its sensitive nature and the reluctance of members to undertake serious reform these findings are robust to various slices of the data and recent advances in the specification and estimation of the gravity equation to account for sample selection issues and the extensive margin of trade copyright 2012 oxford university press

incorporating post zonal reserve deployment transmission constraints into energy and ancillary service co optimization this paper presents a new approach implemented in miso day ahead and real time energy and ancillary service market clearing processes to address the reserve deliverability issue in this approach miso enhanced the co optimization process to incorporate post zonal reserve deployment transmission constraints reserves are procured within the co optimization to meet both market wide reserve requirements and ensure their deliverability on a zonal basis as a result zonal market clearing prices mcps for reserves can properly reflect the effects of zonal reserve deployment on transmission constraints under consideration

stochastic multiobjective market clearing of joint energy and reserves auctions ensuring power system security in this paper a stochastic multiobjective framework is proposed for day ahead joint market clearing the proposed multiobjective framework can concurrently optimize competing objective functions including augmented generation offer cost and security indices overload index voltage drop index and voltage stability margin besides system uncertainties including generating units and branches contingencies and load uncertainty are explicitly considered in the stochastic market clearing scheme the solution methodology consists of two stages which firstly employs roulette wheel mechanism and monte carlo simulation mcs for random adaptive 24 h scenario generation wherein the stochastic multiobjective market clearing procedure is converted into its respective deterministic equivalents scenarios in the second stage for each deterministic scenario a multiobjective mathematical programming mmp formulation based on the epsiv constrained approach is implemented for provision of spinning reserve sr and nonspinning reserve nsr as well as energy the mmp formulation of the market clearing process is optimized while meeting ac power flow constraints and expected interruption cost eic the ieee 24 bus reliability test system rts 24 bus is used to demonstrate the performance of the proposed method

price hike of staple food nutritional impact and consumption adjustment evidence from the 2005 2010 rice price increase in rural bangladesh this paper studies the nutritional impact of the rice price increase between 2005 and 2010 on households in rural bangladesh and their resulting adjustment in consumption of rice non rice food and

multiperiod auction for a pool based electricity market this paper presents a market clearing tool for the market operator of a pool based electricity market for energy this tool is transparent and fair for the market participants and simple to implement and to interpret it preserves the privacy of the corporate information of the participants and provides the right signals to achieve economic efficiency furthermore it recognizes and properly models the technical physical and inter temporal constraints of the participant thermal power generators from a mathematical point of view the proposed tool results in a mixed integer linear programming problem that can be efficiently solved using currently available branch and cut software to illustrate the adequate functioning of the proposed market clearing procedure different realistic case studies are analyzed in detail

under the weather health schooling and economic consequences of early life rainfall life in rural areas of developing countries is prone to many kinds of risk such as illness or mortality of household members crop or other income loss due to natural phenomena weather insect infestations or fire for example and civil conflict in addition to their contemporaneous effects the effects of certain types of shocks may still be felt many years or even decades later from a public policy standpoint it is particularly important to identify shocks that have large long run effects moreover the mechanics underlying the persistence of shocks may be of con siderable interest for example a health shock may have a long run effect simply because the health shock itself persists over time alternately the health shock may not directly affect long run outcomes but it could affect some other outcome such as educational attainment that helps determine long run well being in this paper we focus on shocks that occur at the very beginning of life we ask how sensi tive long run individual well being is to environmental conditions around the time of birth in particular we examine the effect of weather shocks around the time of birth on the adult health education and socioeconomic outcomes of indonesian women and men born between 1953 and 1974 in addition we attempt to shed light on the intervening pathways connecting early life rainfall to adult outcomes illuminating the roles of health and educational attainment in deter mining adult socioeconomic status this investigation has considerable data requirements it necessitates information on weather shocks experienced by individuals several decades earlier as well as detailed current informa tion on adult outcomes we use information in the indonesian family life surveys ifls on an individual s year and location of birth and link each individual in that survey to locality specific rainfall data for their birth year for individuals born in rural areas on whom we focus rainfall variation across space and time should generate corresponding variation in agricultural output and thus household income to deal with measurement error in the rainfall data we run instrumental variables regressions where variables for rainfall measured at slightly more distant rainfall stations serve as instruments for rainfall in the individual s birthplace and birth year we examine the impact of early life rainfall on a range of adult outcomes observed in 2000 we find that higher early life rainfall leads to improved health schooling and socioeconomic status for women women with 20 percent higher rainfall relative to normal local rainfall in their year and location of birth are 3 8 percentage points less likely to self report poor or very poor health they attain 0 57 centimeters greater height attain 0 22 more completed grades of

a two season agricultural household model of output and price uncertainty abstract this paper presents a two season model of a household s production consumption labor supply and storage decisions in an environment of output and price risk the analytical results in this study are markedly different from those of models prevalent in the mainstream of the agricultural household literature the empirical analysis that uses panel data from a village in india provides support for the theoretical results and underscores the seasonal dimension of the farmers choice problems the results also show that ignoring risk or risk averse preferences may introduce substantial downward bias in optimal response estimates

incentives information and malnutrition evidence from an experiment in india abstract this study provides one of the first pieces of evidence comparing the effectiveness of different performance pay contracts among caregivers to improve child health we carry out a cluster randomized controlled trial in urban slums of kolkata india covering 209 childcare centers to test three separate performance pay treatments in addition to providing information on the demand side we promise low or high absolute performance incentives to public sector caregivers where each bonus is based on improvements in health of 3 6 year old children under their care we also test for the impact of relative incentives where the bonus depends upon a worker s performance relative to her peers all mothers in the treatment arms are also provided nutritional information high absolute incentives to workers combined with nutritional information to mothers works to reduce severe malnutrition by 5 percentage points over three months relative incentives and low absolute incentives show no significant improvements in child health on average

do wto members have more liberal trade policy abstract this paper uses 68 measures of trade policy and liberalization to ask if membership in the world trade organization wto and its predecessor the general agreement on tariffs and trade gatt is associated with more liberal trade policy almost no measures of trade policy are significantly correlated with gatt wto membership trade liberalizations when they occur usually lag gatt entry by many years and the gatt wto often admits countries that are closed and remain closed for years the exception to the rule is that wto members tend to have slightly more freedom as judged by the heritage foundation s index