do labor market policies have displacement effects evidence from a clustered randomized experiment this article reports the results from a randomized experiment designed to evaluate the direct and indirect displacement impacts of job placement assistance on the labor market outcomes of young educated job seekers in france we use a two step design in the first step the proportions of job seekers to be assigned to treatment 0 25 50 75 or 100 were randomly drawn for each of the 235 labor markets e g cities participating in the experiment then in each labor market eligible job seekers were randomly assigned to the treatment following this proportion after eight months eligible unemployed youths who were assigned to the program were significantly more likely to have found a stable job than those who were not but these gains are transitory and they appear to have come partly at the expense of eligible workers who did not benefit from the program particularly in labor markets where they compete mainly with other educated workers and in weak labor markets overall the program seems to have had very little net benefits

the pitfalls of work requirements in welfare to work policies experimental evidence on human capital accumulation in the self sufficiency project abstract this paper investigates whether policies that encourage recipients to exit welfare for full time employment influence participation in educational activity the self sufficiency project ssp was a demonstration project where long term welfare recipients randomly assigned to the treatment group were offered a generous earnings supplement if they exited welfare for full time employment we find that treatment group members were less likely to upgrade their education along all dimensions high school completion enrolling in a community college or trade school and enrolling in university thus work first policies that encourage full time employment may reduce educational activity and may have adverse consequences on the long run earnings capacity of welfare recipients we also find that there was a substantial amount of educational upgrading in this population for instance among high school dropouts at the baseline 19 completed their diploma by the end of the demonstration finally we simulate the consequences of the earnings supplement in the absence of adverse effects on educational upgrading doing so alters the interpretation of the lessons from the ssp demonstration

indirect effects of an aid program how do cash transfers affect ineligibles consumption cash transfers to eligible households indirectly increase the consumption of ineligible households living in the same villages this effect operates through insurance and credit markets ineligible households benefit from the transfers by receiving more gifts and loans and by reducing their savings thus the transfers benefit the local economy at large looking only at the effect on the treated underestimates the impact one should analyze the effects of this class of programs on the entire local economy rather than on the treated only and use a village level randomization rather than selecting treatment and control subjects from the same community

economic mobility and poverty dynamics in developing countries this study provides an introduction to this special issue of the journal of development studies on economic mobility and poverty dynamics in developing countries in addition to providing a conceptual framework it outlines how the contributions fit into the extant literature a series of regularities emerge across these studies the poor consist of those who are always poor poor at all dates and those who move in and out of poverty with the latter group tending to be strikingly large such movements in and out of poverty are apparent when looking at poverty in either absolute or relative terms changes in returns to endowments can be a potent source of increased incomes finally seemingly transitory shocks can have long term consequences the study concludes by drawing out the policy implications of these regularities

micro data heterogeneity and the evaluation of public policy nobel lecture this paper summarizes the contributions of microeconometrics to economic knowledge four main themes are developed 1 microeconometricians developed new tools to respond to econometric problems raised by the analysis of the new sources of micro data produced after the second world war 2 microeconometrics improved on aggregate time series methods by building models that linked economic models for individuals to data on individual behavior 3 an important empirical regularity detected by the field is the diversity and heterogeneity of behavior this heterogeneity has profound consequences for economic theory and for econometric practice 4 microeconometrics has contributed substantially to the scientific evaluation of public policy

post reform forestland markets in china land markets developed rapidly in china after agricultural land tenure reforms but not after forest reforms we surveyed farmers in three provinces to examine the post reform forestland markets and options to strengthen them using household choice experiments we estimate land market demand and supply under alternative contractual arrangements our findings are consistent with the currently thin markets but also suggest that alternative institutional and contractual conditions could support broader participation in land markets strengthening property rights on forestland emerges as an especially effective possible policy instrument we illustrate its predicted effects on equilibrium rental rates and market participation

the estimation of wage gains and welfare gains in self selection models the authors modify the basic self sele ction model for the effects ofeducation training unions and other activities on wages by including heterogeneity of rewards to the activity i e diffe rences across individuals in the rate of return to the activity the authors sho w that such heterogeneity creates a new form of selectionbias they provide tes ts for its presence and draw out its implications for the wage and welfare gains to the activity an empirical application provides strong support for such hete rogeneityin one particular training program copyright 1987 by mit press

quality and quantity in primary care mixed payment models evidence from family health organizations in ontario abstract we study the impact of a mixed capitation model the family health organization fho on quality and quantity outcomes among primary care physicians in ontario using a panel of administrative data covering one year before and two years after the fho model was introduced we find that physicians in the fho model provide about 6 to 7 fewer services and visits per day but are between 7 and 11 more likely to achieve preventive care quality targets these results suggest that the mixed capitation model with contractible quality indicators may be welfare improving relative to the ffs model

the social experiment market social experiments are field studies of social programs in which individuals households or in rare instances firms or organizations are randomly assigned to two or more alternative policy interventions or treatments treatments tested by social experiments have included negative income taxes low income housing assistance co insurance rates re employment bonuses welfare to work initiatives job training time of day electric rates and case management models of human service delivery the results of such experiments not only supply the public with policy relevant information but also provide employment and insight to economists this article examines the social experiments market and the characteristics of the rather complex product exchanged in this market we investigate the social experiment industry with data extracted from the digest of social experiments greenberg and shroder 1997 augmented by interviews with buyers and sellers in the market to qualify for a 2 3 page entry in the digest the human subjects had to be randomly assigned among the treatments each of which could involve different incentives opportunities or constraints data were then collected on market and or fiscal outcomes and subjected to professional evaluation the definition of experiment used for the digest and this article is deliberately narrow we do not cover the numerous evaluations of social programs

working life well being and welfare reform motivation and institutions revisited summary this article revisits the relation between economic institutions and motives to work it proposes moving away from a dominant polemical focus on the impact of a single source of security income support towards a multi factorial analysis based on control over working life as a source of well being and motivation to work drawing on surveys of two urban constituencies in sao paulo brazil it is found that income security supports an aristotelian principle of work motivation as individual development however labour market institutions and opportunity levels affect this link implications include a need to consider the distribution of economic control as a key aspect of both human and economic development

instruments randomization and learning about development there is currently much debate about the effectiveness of foreign aid and about what kind of projects can engender economic development there is skepticism about the ability of econometric analysis to resolve these issues or of development agencies to learn from their own experience in response there is increasing use in development economics of randomized controlled trials rcts to accumulate credible knowledge of what works without overreliance on questionable theory or statistical methods when rcts are not possible the proponents of these methods advocate quasirandomization through instrumental variable iv techniques or natural experiments i argue that many of these applications are unlikely to recover quantities that are useful for policy or understanding two key issues are the misunderstanding of exogeneity and the handling of heterogeneity i illustrate from the literature on aid and growth actual randomization faces similar problems as does quasi randomization notwithstanding rhetoric to the contrary i argue that experiments have no special ability to produce more credible knowledge than other methods and that actual experiments are frequently subject to practical problems that undermine any claims to statistical or epistemic superiority i illustrate using prominent experiments in development and elsewhere as with iv methods rct based evaluation of projects without guidance from an understanding of underlying mechanisms is unlikely to lead to scientific progress in the understanding of economic development i welcome recent trends in development experimentation away from the evaluation of projects and toward the evaluation of theoretical mechanisms jel c21 f35 o19

technological change rediscovering the engine of productivity growth in china s rural economy abstract this paper focuses on measuring the relative importance of the role of technology versus that of institutional innovation in china s rural economy a six equation rice sector model explaining provincial level technology adoption yield and factor demand are econometrically estimated using data from china s 13 rice growing provinces for the period 1975 1990 growth decomposition analysis identifies technology adoption as the most important determinant of rice yield growth during 1978 1984 accounting for nearly 40 percent the change institutional reform accounted for 35 percent of the growth in 1985 1990 technology accounts for all of the increase in rice yields the study demonstrates earlier studies may have over estimated the impact of decollectivization

the economics of poverty traps and persistent poverty an asset based approach abstract longitudinal data on household living standards open the way to a deeper analysis of the nature and extent of poverty while a number of studies have exploited this type of data to distinguish transitory from more chronic forms of income or expenditure poverty this paper develops an asset based approach to poverty analysis that makes it possible to distinguish deep rooted persistent structural poverty from poverty that passes naturally with time due to systemic growth processes drawing on the economic theory of poverty traps and bifurcated accumulation strategies this paper briefly discusses some feasible estimation strategies for empirically identifying poverty traps and long term persistent structural poverty as well as relevant extensions of the popular foster greer thorbecke class of poverty measures the paper closes with reflections on how asset based poverty can be used to underwrite the design of persistent poverty reduction strategies

viewpoint estimating the causal effects of policies and programs estimation inference and interpretation of the causal effects of programs and policies have all advanced dramatically over the past 25 years we highlight three particularly important intellectual trends an improved appreciation of the substantive importance of heterogeneous responses and of their methodological implications a stronger focus on internal validity brought about by the credibility revolution and the scientific value that follows from grounding estimation and interpretation in economic theory we discuss a menu of commonly employed partial equilibrium approaches to the identification of causal effects emphasizing that the researcher s central intellectual contribution always consists of making an explicit case for a specific causal interpretation given the relevant economic theory the data the institutional context and the economic question of interest we also touch on the importance of general equilibrium effects and full cost benefit analyses

escaping poverty and becoming poor in 36 villages of central and western uganda abstract twenty four per cent of households in 36 village communities of central and western uganda have escaped from poverty over the past 25 years but another 15 per cent have simultaneously fallen into poverty a roughly equal number of households escaped from poverty in the first period ten to 25 years ago as in the second period the last ten years examined here however almost twice as many households fell into poverty during the second period as in the first period progress in poverty reduction has slowed down as a result multiple causes are associated with descent into poverty and these causes vary significantly between villages in the two different regions for nearly two thirds of all households in both regions however ill health and health related costs were a principal reason for descent into poverty escaping poverty is also associated with diverse causes which vary across the two regions compared to increases in urban employment however land related reasons have been more import

subsidy or market reform rethinking china s farm consolidation strategy chinese food security policy is anchored increasingly on the conviction that domestic grain production should be greatly enhanced and the best way to do so is to expand farm production scale to that end an increasing stream of public investment has been directed to the grain sector in the form for example of farm expansion subsidies our purpose is to assess the potential impacts of china s farm scale expansion on both yields and per hectare economic returns analysis of a large sample of farm household production data finds with some exceptions that grain yields likely will decline as farm size grows compromising food self sufficiency targets more importantly in only isolated cases would per hectare economic returns decline with size thus an emphasis on reducing farmland transactions costs may stimulate cropland consolidation and achieve the desired long term structural transformation

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

specialization diversification and productivity a panel data analysis of rice farms in korea this article examines the microeconomics of productivity associated with specialization diversification in production activities with an application to korean rice farms korean rice farms tend to be very small and highly specialized our analysis examines the productivity effects associated with both farm size and farm specialization diversification in korean agriculture relying on farm level panel data the analysis studies farm productivity in a multi input multi output context accounting not only for changes in inputs and technical change in rice production but also for the role of diversification in the production of other crops in current and previous periods we find positive but small productivity gains from farm diversification these gains come mostly from complementarity effects across farm outputs with minimal effect of scale economies the positive complementarity effects work against nonconvexity effects which provide strong productivity incentives for rice farms to specialize

economic response to a guaranteed annual income experience from canada and the united states this article reviews research from the five income maintenance experiments in canada and the united states after sketching the historical and political context of the experiments we compare their designs and discuss some important analytic difficulties our primary focus is the work incentive issue both nonstructural estimates of the experimental effects and elasticity estimates of structural labor supply functions we provide initial estimates of nonstructural and structural models for the canadian experiment we discuss more briefly some non work response findings associated with a guaranteed annual income and offer some personal comments on social experimentation and the policy process

welfare dynamics in rural kenya and madagascar this paper presents comparative qualitative and quantitative evidence from rural kenya and madagascar in an attempt to untangle the causality behind persistent poverty we find striking differences in welfare dynamics depending on whether one uses total income including stochastic terms and inevitable measurement error or the predictable structural component of income based on a household s asset holdings our results suggest the existence of multiple dynamic asset and structural income equilibria consistent with the poverty traps hypothesis furthermore we find supporting evidence of locally increasing returns to assets and of risk management behaviour consistent with poor households defence of a critical asset threshold through asset smoothing

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

the pre programme earnings dip and the determinants of participation in a social programme implications for simple programme evaluation strategies the key to estimating the impact of a programme is constructing the counterfactual outcome representing what would have happened in its absence this problem becomes more complicated when agents such as individuals firms or local governments self select into the programme rather than being exogenously assigned to it this paper uses data from a major social experiment to identify what would have happened to the earnings of self selected participants in a job training programme had they not participated in it we investigate the implications of these earnings patterns for the validity of widely used before after and difference in differences estimators

the rapid rise of china s dairy sector factors behind the growth in demand and supply with the rapid growth in china s dairy industry a number of recent papers have addressed either the supply or the demand trends for dairy products in china none however presents a systematic explanation for the recent growth in both the supply and demand for dairy products the goal of this paper is to sketch a more comprehensive picture of china s dairy sector and to assess the nature of the sector s development in the coming decades drawing upon several empirical studies we examine the trends in dairy product consumption to create a composite picture of the factors underlying the recent growth we also empirically investigate the sources of production gains in milk supply and assess the relative importance of expanding herd size changes in the nature of production technological change and improvements in efficiency to the overall growth of milk production

comparing features of convenient estimators for binary choice models with endogenous regressors abstract we discuss the relative advantages and disadvantages of four types of convenient estimators of binary choice models when regressors may be endogenous or mismeasured or when errors are likely to be heteroscedastic for example such models arise when treatment is not randomly assigned and outcomes are binary the estimators we compare are the two stage least squares linear probability model maximum likelihood estimation control function estimators and special regressor methods we specifically focus on models and associated estimators that are easy to implement also for calculating choice probabilities and regressor marginal effects we propose the average index function aif which unlike the average structural function asf is always easy to estimate

china s food economy to the twenty first century supply demand and trade this paper accounts for the structural changes now taking place in china and suggests that china is not likely to become either an enormous importer or exporter of grain ultimately though china s grain balances will depend on decisions made by chinese policymakers rather than natural resource constraints p v this abstract was borrowed from another version of this item

general equilibrium treatment effects a study of tuition policy this paper defines and estimates general equilibrium treatment effects the conventional approach in the literature on treatment effects ignores interactions among individuals induced by the policy interventions being studied focusing on the impact of tuition policy and using estimates from our dynamic overlapping generations general equilibrium model of capital and human capital formation we find that general equilibrium impacts of tuition on college enrollment are an order of magnitude smaller than those reported in the literature on microeconomic treatment effects the assumptions used to justify the late parameter in a partial equilibrium setting do not hold in a general equilibrium setting policy changes induce two way flows we extend the late concept to a general equilibrium setting we present a more comprehensive evaluation to program evaluation by considering both the tax and benefit consequences of the program being evaluated and placing the analysis in a market setting this abstract was borrowed from another version of this item

prohibition of factor market exchanges and technological choice in chinese agriculture this article constructs a model of technological choice in an economy where market exchanges in land and labour are prohibited empirical data on demand for tractors tractor usage and chemical fertilisers in china are employed to test several hypotheses derived from the theoretical model the theory implies that the impact of relative factor scarcity on the pattern of technological choice in such an economy is similar to that in a market economy as postulated by the hicks ruttan hayami binswanger hypothesis of induced technological change the empirical evidence is found to be consistent with the implications of the model

agricultural supply response a survey abstract this paper surveys the literature on agricultural supply response to prices in developing countries empirical estimates of elasticities depend both on the methodology adopted and on country specific factors relating to technology economic structure and macro constraints the paper seeks to establish some general conclusions on supply responsiveness within these limitations supply response to output prices at the aggregate and at the crop levels is considered first crop specific acreage elasticities range between zero and 0 8 in the short run while long run elasticities tend to be higher between 0 3 and 1 2 yield elasticities are smaller and less stable than acreage elasticities clearly inter crop pricing can be relied upon to effect shifts in the commodity composition of agricultural output evidence also suggests that supply elasticities vary systematically with such factors as price and yield risks multiple cropping the importance of the crop farm incomes farm size tenancy and literacy the most controversial and important aspect of supply response is the effect on aggregate agricultural output of agriculture s terms of trade conventional time series estimates range from 0 1 to 0 3 a major cross country study reports an aggregate elasticity as high as 1 66 it is argued that cross country estimates are apt to exaggerate aggregate responsiveness while time series studies underestimate it somewhat for ldcs a tentative range of 0 4 to 0 5 seems plausible hence the distributive effects of the terms of trade are likely to be more significant than the allocative effects asian evidence shows that only a third of the inter country differences in fertilizer use can be attributed to fertilizer price policies provided new technologies and infrastructure are in place fertilizer subsidies can help in technology diffusion and in over coming credit constraints the choice between price supports and input subsidies will depend on a variety of country or situation specific factors nevertheless a significant general factor favoring price supports is that they can more easily be coupled with price stabilization goals than input subsidies though sparse the available evidence on the response of marketed surplus suggests that price policy is not a reliable instrument for regulating inter sectoral trade

the impact of china s economic reforms on agricultural productivity growth this paper presents a method for assessing the relative importance of price increases and strengthened individual incentives due to the introduction of the responsibility system for the post 1978 increase in china s agricultural productivity data on post 1978 chinese agricultural performance suggest that a little over three quarters of the measured productivity increase is due to payment system changes and the remainder to price increases we also use our method to calculate incentive indices giving an estimate of the fraction of their marginal product that peasants received under the pre 1978 regime

who stays poor who becomes poor evidence from the british household panel survey we estimate a first order markov model of poverty persistence and entry rates for working age britons and demonstrate the importance of controlling for endogenous selection via initial poverty status and attrition predicted poverty transition rates reveal substantial heterogeneity in poverty transition rates but there is also substantial genuine state dependence in poverty

the household responsibility system reform and the adoption of hybrid rice in china abstract this paper studies the diffusion of hybrid rice before and after the recent institutional change from the collective team system to the household based farming system in rural china a simple model which treats the adoption of hybrid rice as a portfolio selection problem is presented the model is tested against time series cross county data collected from hunan province in south china the empirical evidence suggests that 1 adoption behavior in the collective system was not consistent with the predictions of the theoretical model this evidence indicates the existence of administrative intervention in influencing production decisions in the collective system 2 there was a significant change in the structure of the adoption function following the transition from the collective system to the household based system and 3 adoption behavior in the household system is consistent with the predictions of the theoretical model

irrigation agricultural performance and poverty reduction in china the overall goal of our paper is to understand the impact that irrigation in china has had on grain production and incomes in general and income and poverty alleviation in poor areas in particular the paper seeks to meet three objectives first we describe the relationship among irrigation status yields and household crop revenue second we seek to understand the magnitude and nature of the effect that irrigation has on yields and crop revenue finally we seek to understand the impact that irrigation has on incomes in poor areas our analysis shows that irrigation contributes to increases in yields for almost all crops and in income for farmers in all areas the importance of crop income in poor areas and the strong relationship between crop revenue and irrigation provides evidence of the importance of irrigation in past and future poverty alleviation in china we also show that in the majority of the villages that invested in new irrigation returns are positive even after accounting for increases in capital and production costs 2005 elsevier ltd all rights reserved

plan and market in china s agricultural commerce this article examines interactions between markets and state commercial planning in the context of china s agricultural sector it begins with a discussion of recent trends in agricultural planning and commerce in china and then presents a theoretical model that analyzes the way that a mixed commercial system of the sort observed in china functions the theoretical analysis suggests that a mixed system is sustainable and can have desirable efficiency and distributional effects markets however limit the range of sustainable plans and in the presence of markets state planning may no longer directly influence production and consumption behavior

selection on observed and unobserved variables assessing the effectiveness of catholic schools in this paper we measure the effect of catholic high school attendance on educational attainment and test scores because we do not have a good instrumental variable for catholic school attendance we develop new estimation methods based on the idea that the amount of selection on the observed explanatory variables in a model provides a guide to the amount of selection on the unobservables we also propose an informal way to assess selectivity bias based on measuring the ratio of selection on unobservables to selection on observables that would be required if one is to attribute the entire effect of catholic school attendance to selection bias we use our methods to estimate the effect of attending a catholic high school on a variety of outcomes our main conclusion is that catholic high schools substantially increase the probability of graduating from high school and more tentatively attending college we find little evidence of an effect on test scores

is the threat of reemployment services more effective than the services themselves evidence from random assignment in the ui system we examine the effect of the worker profiling and reemployment services system this program profiles unemployment insurance ui claimants to determine their probability of benefit exhaustion and then provides mandatory employment and training services to claimants with high predicted probabilities using a unique experimental design we estimate that the program reduces mean weeks of ui benefit receipt by about 2 2 weeks reduces mean ui benefits received by about 143 ana increases subsequent earnings by over 1 050 most of the effect results from a sharp increase in early ui exits in the treatment group relative to the control group jel j650

evaluating the econometric evaluations of training programs with experimental data this paper takes the results of an employment and training program thatwas run as a field experiment in which the participants were randomlyassigned into a treatment or a control group and compares these results to the estimates that might have been produced by an econometrician who evaluated the program using the same econometric procedures that have been used in the program evaluation literature this comparison shows that many of these econometric procedures fail toreplicate the experimentally determined results and suggests that researchers should be aware of the potential for specification errorsin other nonexperimental evaluations copyright 1986 by american economic association

marketing reforms market development and agricultural production in china abstract chinese agricultural reforms have consisted of two transitional stages initially decollectivization in the late 1970s followed by market liberalization in the mid 1980s while much research has been conducted on the initial stage of increasing the incentives for farmers in collective cultivation little quantitative evidence exists on how marketing reforms and the development of rural markets has affected agricultural production decisions using more accurate and disaggregated measures of the reform and market development components of liberalization than previous research this study examined the effects of these liberalization policies on the agricultural production decisions in shaanxi province procurement quota levels were found to be positively associated with the area planted to grain crops thus quotas represent an effective way of increasing grain production and thereby also a means of achieving food self sufficiency which remains an important policy objective for the chinese government the involvement of state grain stations in free market grain trade and the expansion of rural markets has increased the area planted to the two potential cash crops soybeans and wheat and reduced the sown area of the subsistence crop corn reflecting the reduced need to plant corn as a self insurance mechanism for smoothing consumption an increase in procurement quotas increases fertilizer use on grain crops due to the policy of linking quotas to access to below market priced fertilizer but decreases the use of labor which shifts to other more profitable enterprises market development has increased these off farm employment opportunities and the earnings associated with them thereby promoting the shift of labor out of crop production and increased the use of fertilizer which has also become more available

growth in china s grain production 1978 1997 a disaggregate analysis abstract this paper analyzes china s grain production during 1978 97 using disaggregate approach to explore disparities in growth patterns of respective crops the study reveals that during this period almost all the increased output can be attributed to the growth of rice wheat and corn the contribution of other crops as a whole was almost negligible the disparities in growth patterns were partly the result of crop adjustments induced by changes in food demand and dominated by substitutions of high yield crops for low yield crops in this process the adoption of new technologies played an important role varying opportunity costs of grain production in different areas also affected growth patterns of respective crops the trend in china s grain production in the past two decades suggests that the adherence to grain self sufficiency has become not only increasingly costly but also unnecessary

separability in farm household economics an experiment with linear programming abstract the assumption of separability between farm household production and consumption facilitates analysis but entails several important restrictions the implications of assuming separability are discussed here in relation to the modelling of a representative tongan farm household econometric estimation of household demand is coupled with a linear programming lp model of farm household production when analysing consumer demand separable farm household economics is undoubtedly preferable to ignoring the production consumption linkages entirely however the restrictions which must be imposed on the production side of the separable model are such that a realistic lp solution is unlikely to be obtained this is likely to be a major deterrent to adopting the separable approach for studies in which the main focus is on production rather than consumption

estimating marginal returns to education this paper estimates marginal returns to college for individuals induced to enroll in college by different marginal policy changes the recent instrumental variables literature seeks to estimate this parameter but in general it does so only under strong assumptions that are tested and found wanting we show how to utilize economic theory and local instrumental variables estimators to estimate the effect of marginal policy changes our empirical analysis shows that returns are higher for individuals with values of unobservables that make them more likely to attend college we contrast our estimates with iv estimates of the return to schooling

china s government finance and food security nexus a regime switching analysis this paper is an empirical assessment of the government finance and food security nexus in china from 1978 to 2016 using autoregressive distributed lag for linear and threshold cointegration the

economies of scale and mechanization in chinese corn and wheat production as the growth in chinese farm productivity slowed down between 2000 and 2010 modernizing agriculture has become a priority of the chinese government given the important role of mechanization and

incorporating nonmarket time into benefit cost analyses of social programs an application to the self sufficiency project abstract benefit cost analysis is used extensively in the evaluation of social programs often the success or failure of these programs is judged on the basis of whether the calculated net benefits to society are positive or negative almost all existing benefit cost studies of social programs count entire increases in income accruing to participants in a social program as net benefits to society however economic theory implies that the conceptually appropriate measure of the impact of a government program on any group of individuals is the net change in their surplus or economic rent rather than the net change in their income for example if a social program causes increases in income by increasing work hours then the lost nonmarket time that accompanies these increases has value that needs to be counted as a cost when assessing the merits of that program in this paper we develop a methodology for incorporating lost nonmarket time into benefit cost analyses of social programs we apply our methodology to the self sufficiency project ssp an experimental welfare to work program tested on a pilot basis in two provinces in canada during the 1990s we find that if losses in nonmarket time are ignored ssp yields a substantial positive net benefit to society however if losses in nonmarket time are taken into account the net societal benefits are greatly reduced even becoming negative in certain instances we conclude that future benefit cost analyses of social programs must take effects on nonmarket time into account in order to give a more accurate picture of the net benefits of the program

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

rural reforms and agricultural growth in china this paper employs province level panel data to assess the contributions of decollectivization price adjustments and other reforms to china s agricultural growth in the reform period decollectivization is found to improve total factor productivity and to account for about half of the output growth during 1978 84 the adjustment in state procurement prices also contributed positively to output growth its impact came mainly from the responses in input use the effect of other market related reforms on productivity and output growth was very small reasons for slowdown in agricultural growth after 1984 are also analyzed copyright 1992 by american economic association

the compelling effects of compulsory schooling evidence from canada abstract compulsory school laws have existed for more than a hundred years and policies to mandate further education continue to be discussed the implications of these laws however are not well understood historical changes to compulsory schooling in canada permit an examination of their effects on would be dropouts under very different circumstances than those during changes in other countries mandating education substantially increased adult income and substantially decreased the likelihood of being below the low income cut off unemployed and in a manual occupation these findings suggest significant gains from this legislation which seem unlikely offset by the costs incurred while having to remain in school jel classification i20 i28

the changing structure of the world rice market 1950 2000 abstract the world rice market has been unstable for much of its post world war ii history with prices volatile and the availability of supplies uncertain these characteristics exemplified by the world food crisis of the mid 1970s influenced domestic price and production policies in a number of asian countries however the structure of the world rice market has evolved and changed during the past 50 years this paper identifies three distinct phases in the history of the market based on trends in the level and stability of production and the trade orientation of major exporters the level and stability of production increased steadily over the entire period exporters have generally been active in the world market with the period 1965 1981 being an important exception since the mid 1980s prices have been low and quite stable and the patterns identified in the paper suggest that prices will remain so in the future the policy implication is that asian rice importers can afford to rely more on the world market than was warranted in the past

human capital investment and the gender division of labor in a brawn based economy we use a model of human capital investment and activity choice to explain facts describing gender differentials in the levels and returns to human capital investments these include the higher return to and level of schooling the small effect of healthiness on wages and the large effect of healthiness on schooling for females relative to males the model incorporates gender differences in the level and responsiveness of brawn to nutrition in a roy economy setting in which activities reward skill and brawn differentially empirical evidence from rural bangladesh provides support for the model and the importance of the distribution of brawn

food self sufficiency comparative advantage and agricultural trade a policy analysis matrix for chinese agriculture revised china s rapid economic growth and gradual transition toward a market economy have brought about significant changes in production and consumption patterns and trade behavior in agriculture in this study the authors assess the comparative advantage and protection of china s major agricultural crops using a modified policy analysis matrix ipami and data from 1996 to 1998 results strongly suggest that china has a comparative advantage in labor intensive crops and a disadvantage in land intensive crops

poverty population and environmental degradation in china this paper studies the relationship among population poverty and the environmental factors and the impact they have had on china s land water forests and pastures it does so by examining the extent of environmental degradation and china s success in controlling its environmental problems is reviewed by investigating how the leadership has tried to develop a legal framework and series of institutions to carry out environmental policy and by providing empirical evidence demonstrating the determinants of the successes that china has achieved in surmounting or slowing some of its environmental problems five of china s rural resource concerns are surveyed in this paper water pollution deforestation destruction of the grasslands soil erosion and salinization the paper finds that government policy has not been effective in controlling rural resource degradation primarily because it has limited fiscal resources and poorly trained personnel and under these constraints the government has delegated responsibility for environmental and resource protection to the ministries of agriculture and forestry two institutions that have an incentive to favor pro production policies instead china s efforts to alleviate policy integrate markets and control population appear to have helped mitigate a number of adverse environmental consequences of china s development effort of the last 40 years

exploring poverty traps and social exclusion in south africa using qualitative and quantitative data abstract recent theoretical work hypothesises that a polarised society like south africa will suffer a legacy of ineffective social capital and blocked pathways of upward mobility that leaves large numbers of people trapped in poverty to explore these ideas this paper employs a mix of quantitative and qualitative methods novel econometric analysis of asset dynamics over the 1993 98 period identifies a dynamic asset poverty threshold that signals that large numbers of south africans are indeed trapped without a pathway out of poverty qualitative analysis of this period and the period 1998 2001 more deeply examines patterns of mobility and confirms the continuation of this pattern of limited upward mobility and a low level poverty trap in addition the qualitative data permit a closer look at the specific role played by social relationships while finding ample evidence of active social capital and networks these are more helpful for non poor households for the poor social capital at best helps sta

success and failure of reform insights from the transition of agriculture this paper analyzes the linkages between the reform strategies in transition countries and economic performance the authors focus on agriculture because of the sharpness of the policy changes fundamental differences among countries and relative simplicity of agricultural relationships the authors document post reform performance in the transition countries of asia and europe the authors show how a pricing reform and subsidy reductions b land rights reform and policies that affect farm restructuring and c the presence institutions that facilitate exchange either markets or market substitutes affect output and productivity the paper ends with general lessons on reforms and transition

assessing the impact of a school subsidy program in mexico using a social experiment to validate a dynamic behavioral model of child schooling and fertility this paper uses data from a randomized social experiment in mexico to estimate and validate a dynamic behavioral model of parental decisions about fertility and child schooling to evaluate the effects of the progresa school subsidy program and to perform a variety of counterfactual experiments of policy alternatives our method of validation estimates the model without using post program data and then compares the model s predictions about program impacts to the experimental impact estimates the results show that the model s predicted program impacts track the experimental results our analysis of counterfactual policies reveals an alternative subsidy schedule that would induce a greater impact on average school attainment at similar cost to the existing program

effects of technological change and institutional reform on production growth in chinese agriculture recent rapid agricultural production growth in chinese agriculture could be attributed to an increase in inputs technological change and institutional reform an accounting approach was used to separate the relative contribution of these three factors institutional change like the introduction of the household production responsibility system has contributed to past growth in production however technological change is crucial to furthering production growth because of the limited potential for significant increase in the use of conventional inputs in particular land continued institutional change must accompany corresponding technological changes

china s agriculture drivers of change and implications for china and the rest of world the overall goal of this article is to identify major changes in china s agriculture food economy and their implications for both china itself and more importantly to the rest of world china has become one of the fastest growing economies in the world since late 1970s gdp grew at about 10 annually in the past 30 years china s experience shows the importance of both domestic and external policies in achieving sustainable growth the results from this study provide significant policy implications to many countries that are currently china s major trade partners or those seeking greater economic and trade relations with china the main conclusions on the implications of china s rapid economic growth are that china s growth will provide more opportunities than challenges to the rest of the world on average overall the rest of the world will gain from china s economic expansion though this general conclusion may not hold for some countries

better late than nothing some comments on deaton 2009 and heckman and urzua 2009 two recent papers deaton 2009 and heckman and urzua 2009 argue against what they see as an excessive and inappropriate use of experimental and quasi experimental methods in empirical work in economics in the last decade they specifically question the increased use of instrumental variables and natural experiments in labor economics and of randomized experiments in development economics in these comments i will make the case that this move towards shoring up the internal validity of estimates and towards clarifying the description of the population these estimates are relevant for has been important and beneficial in increasing the credibility of empirical work in economics i also address some other concerns raised by the deaton and heckman urzua papers

public investment and china s long term food security under wto abstract as the world s most populous nation china has taken various measures to increase grain production output in the past several decades however many of the policy interventions to promote grain production are not in conformity with wto rules and also lead to misallocation of resources and loss of production efficiency while adequately steady growth of grain output may still be a policy goal for the world s most populous nation with continuous population growth and economic development it is crucial that the country moves away from many of its past measures and explores alternative policy tools to strengthen domestic grain production by using agricultural research and irrigation as a proxy this paper examines the effects of public investment in irrigation and agricultural research on the output increase of grain production in china in a crop specific manner the research finds that increasing public investment in agricultural research will bring about higher output in a cost effective manner increasing public investment in agricultural r d etc should be considered with high priority in the future to be utilized as a policy tool to enhance long term food security

the integration of child tax credits and welfare evidence from the national child benefit program abstract in 1998 the canadian government introduced a new child tax credit the innovation in the program was its integration with social assistance welfare some provinces agreed to subtract the new federally paid benefits from provincially paid social assistance partially lowering the welfare wall other provinces did not integrate benefits providing a quasi experimental framework for estimation we find large changes in social assistance take up and employment in provinces that provided the labour market incentives to do so in our sample the integration of benefits can account for between 19 and 27 of the decline in social assistance receipt between 1997 and 2000

shocks and their consequences across and within households in rural zimbabwe abstract increasing attention is now being paid to poverty dynamics in developing countries this work links the extent to which households smooth consumption or smooth assets given income shocks the empirical evidence on the churning of households in and out of poverty and the possibility that temporary shocks can have permanent consequences using longitudinal data from rural zimbabwe this paper extends the discussion of these issues by disaggregating the impact of shocks by levels of asset holdings by disaggregating the impact of shocks on individual level welfare and by assessing the extent to which such shocks have permanent consequences by doing so it assesses the validity of distinguishing between asset and consumption smoothing and provides insights into whether poverty dynamics assessed at the household level provide an adequate picture of dynamics at the individual level

economies of scale and scope and the economic efficiency of china s agricultural research system this article investigates economies of scale and scope and other potential sources of improvements in the economic efficiency of china s crop breeding an industry at the heart of the nation s food economy using data covering 46 wheatand maize breeding institutes from 1981 to 2000 we estimate cost functions for the production of new varieties at china s wheat and maize breeding institutes our results indicate strong economies of scale along with small to moderate economies of scope related to the joint production of new wheat and maize varieties cost efficiency increases significantly with increases in the breeders educational status and with increases in access to genetic materials from outside the institute

pesticide productivity host plant resistance and productivity in china abstract pesticides are used as the primary method of pest control in asian rice production conditions in china have led to demand for high and increasing rice yields resulting in intensive cultivation and adoption of fertilizer responsive varieties the consequence has been widespread pest infestations many studies have estimated pesticide productivity but few have estimated the productivity of alternative methods of pest control namely host plant resistance none have estimated the substitutability between these methods of pest control the productivity of pesticides and host plant resistance and the substitutability between them is measured using two stage cobb douglas and translog production functions under intensive rice production systems in eastern china pesticide productivity is low compared to the productivity of host plant resistance in fact returns to pesticide use are negative at the margin host plant resistance is an effective substitute for pesticides and substantial reductions in pesticide use could be achieved with no loss in rice production through improvements in host plant resistance these results suggest that pesticides are being overused in eastern china and host plant resistance is being under utilized government policies to promote increased pesticides in rice might be ill advised given the low productivity and negative returns particularly in light of well known negative externalities associated with pesticide use

control in a dynamic village economy the reforms and unbalanced development in china s rural economy abstract a dynamic control framework is used to model the chinese village economy in order to explain the rural sector s unbalanced growth in the post reform period village leaders are assumed to maximize a multi attribute utility function by manipulating local policy instruments subject to the structural relationships in the economy the model s parameters are estimated econometrically using a data set from forty villages in eastern china the empirical results identify important linkages between agriculture and rural industry in village economies unbalanced growth can partially be explained by the way economic incentives induce individuals in rural areas to move resources toward the rural industrial sector and away from agriculture

bridging the gap between partial and total factor productivity measures using directional distance functions technical dependencies as well as data constraints limit our ability to allocate inputs across sectors and hence our ability to measure sectoral productivity we adapt a directional measure of efficiency to the measurement of sector specific productivity that does not require allocating all inputs across sectors applied to the agricultural sector of a group of countries the results show important differences in livestock and crops productivity growth commonly used partial factor productivity measures for livestock and crops tend to overestimate productivity growth in most developing countries while underestimating it in european countries

climbing out of poverty falling back in measuring the persistence of poverty over multiple spells this paper investigates the persistence of poverty over individuals life times using a hazard rate approach that accounts for multiple spells of poverty and incorporates spell duration individual and household characteristics and unobserved heterogeneity the findings highlight the importance of considering multiple spells in an analysis of poverty persistence with half of those who end poverty spells returning to poverty within four years accounting for multiple spells shows that approximately 50 percent of blacks and 30 percent of whites falling into poverty in some year will have family income below the poverty line in five or more of the next ten years

education and allocative efficiency household income growth during rural reforms in china this paper studies the contribution of schooling to rural income in china during factor market liberalization between 1986 and 1995 the relaxation of controls permitted farm households to reallocate productive inputs from agriculture to nonagricultural activities it is hypothesized that education facilitates this adjustment panel data from sichuan province suggest that schooling enhanced the ability of farmers to devote labor and capital to nonfarm production given the evidence that less than optimum levels of these inputs were allocated to nonagricultural uses during the transition the expansion of nonfarm activities contributed significantly to household income growth

does the minimum wage have a higher impact on the informal than on the formal labour market evidence from quasi experiments this article investigates a puzzle in the literature on labour markets in developing countries labour legislations not only have an impact on the formal labour market but also an impact on the informal sector it has even been argued that the impact on the informal sector in the case of the minimum wage is stronger than on the formal sector using quasi experiments of minimum wage changes and thereby exploiting geographical variation of the minimum wage bite i find evidence for this hypothesis informal workers workers without social security contribution experienced significant wage increases when the minimum wage was raised while formal workers did not this result highlights that noncompliance with one labour legislation the social security contribution does not necessarily imply noncompliance to other labour laws such as the minimum wage

the effect of technological imitation on corporate innovation evidence from us patent data abstract technological imitation may play a crucial role in motivating firms to innovate however theoretical predictions and empirical findings on the role of imitation have not yet reached a consensus one major gap in the previous studies is that the empirical tests are based on samples consisting of only one industry over a short period of time this study uses a novel measure of industry level technological imitation proxied by quick citations by competitors to examine the relationship between imitation and innovation using us patent data for the period 1977 2005 we find that there are inverted u shaped relationships between the degree of industry level technological imitation and industry level innovation activities and between the degree of industry level technological imitation and the value of firm level innovation our results suggest that positive externalities from the interactions among firms during the innovation process outweigh the negative effects of free riding concerns on firms innovation activities and incentives to innovate up to a high degree of technological imitation while free riding concerns outweigh the positive externalities when the level of technological imitation is extremely high the sector by sector analyses show that the relationship between technological imitation and the quantity and market value of innovation are not very different across pavitt sectors a comparative analysis on the role of imitation between agglomerated and non agglomerated industries suggests that the positive effect of a moderate level of imitation and the negative effect of an excessive level of imitation are more pronounced for agglomerated industries the results suggest that creating innovation clusters such as silicon valley in the united states and shenzhen city in china and allowing different innovators to cooperate imitate and compete with each other would be very effective in promoting corporate innovation however an excessively high level of technological imitation is more detrimental for firms in innovation clusters because it lowers those firms incentives to innovate more radically

substitution and dropout bias in social experiments a study of an influential social experiment this paper considers the interpretation of evidence from social experiments when persons randomized out of a program being evaluated have good substitutes for it and when persons randomized into a program drop out to pursue better alternatives using data from an experimental evaluation of a classroom training program we document the empirical importance of control group substitution and treatment group dropping out evidence that one program is ineffective relative to close substitutes is not evidence that the type of service provided by all of the programs is ineffective although that is the way experimental evidence is often interpreted

toward a food secure future ensuring food security for sustainable human development in sub saharan africa food security remains a top development priority and global concern it is enshrined in the 2030 agenda for sustainable development in sustainable development goal two food security is also a core component of the human development and capability paradigm since food access and entitlements are critical for reinforcing essential human capabilities in introducing this special issue this paper argues that agriculture is central to improving food security and reducing poverty in africa it suggests that realizing the potential of agriculture in africa requires rapid increases in land productivity and increases in agricultural yields a science based approach that integrates gender and sustainability is critical to meet this goal through the design and implementation of policies that improve the availability farm inputs and farm technology the paper concludes by introducing the papers in this special issue

hybrid rice innovation in china a study of market demand induced technological innovation in a centrally planned economy this paper uses the innovation of hybrid rice in china as a case study to test the validity of the griliches schmookler hypothesis of market demand induced technological innovation in a centrally planned economy the empirical evidence indicates that the size of rice acreage in a province is the major factor in determining the amount of resource allocation for rice research and the adoption intensity of hybrid rice in that province this evidence is consistent with the implication of the griliches schmookler hypothesis copyright 1992 by mit press

poverty dynamics in brazilian metropolitan areas an analysis based on hulme and shepherd s categorization 2002 2011 abstract ever more sophisticated studies on the methodological approach and the conceptual scope of poverty have led to a consensus among scholars on the dynamic characteristic of this phenomenon in other words the existence of an in and out of privation movement of individuals and families within this context hulme and shepherd 2003 defined five groups according to the location of the punctual and average indicators of poverty vis a vis the poverty line this paper s objective is to adapt this typology to brazil using pme monthly job survey micro data for the 2002 2011 timeframe and the six brazilian metropolitan regions covered by pme as well as by estimating a multinomial logit investigate which family characteristics relate to a greater or lesser chance of belonging to each of the chronic and transitory poverty categories categorization allows observation that despite a sweeping across the board decline in the percentage of families in all poverty categories in the past decade those families always or usually poor display demographic socioeconomic access to and insertion into the labor market categories which differ from families in transitory poverty or classified as never poor moreover northeastern metropolitan regions salvador and recife have higher percentages of chronic or transitory poverty multinomial logit estimates make it possible to verify that families whose members have completed secondary schooling or college or hold a higher qualified occupation stand lesser chances of entering into or remaining in poverty results call for differentiating among poor families as they enter into or leave poverty which is tantamount to saying that the dynamics of poverty must be taken into account as public policies are drawn up