Working Papers

Human Capital

– Estimating the Production Function for Human Capital: Results from a Randomized Control Trial in Colombia

with S. Cattan, E. Fitzsimons, C. Meghir and M. Rubio-Codina (May 2017, NBER WP No.20965)

Abstract: We examine the channels through which a randomized early childhood intervention in Colombia led to significant gains in cognitive and socio-emotional skills among a sample of disadvantaged children aged 12 to 24 months at baseline. We estimate the determinants of material and time investments in these children and evaluate the impact of the treatment on such investments. We then estimate the production functions for cognitive and socio-emotional skills. The effects of the program can be explained by increases in parental investments, which have strong effects on outcomes and are complementary to both maternal skills and child’s baseline skills. 
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– Parental Beliefs and Investments in Human Capital

with Flavio Cunha and Pamela Jervis (available soon)

Abstract: We shed light on the importance of parental subjective beliefs in explaining the heterogeneity in parental choices of investments in the development of their children. Subjective beliefs about the production function of skills in early childhood development is crucial since parents may have biased beliefs about the returns to investments, which is crucial to pin down in designing policies aimed at remediating poor investments. To determinate the importance of parental subjective beliefs, we first show how to convert the answers to a specific set of questions into estimates of expected rates of returns on specific investment and then relate these estimates to actual parental behavior, then we formulate and estimate a model in which parents have subjective beliefs about the technology governing the formulation of skill in early childhood development, drawing on detailed and unique data for the identification other model from an early childhood intervention ran in Colombia, in which, home visitors paid weekly visits to randomly chosen households with the aim of promoting child cognitive and psychosocial development and improving mother-child interactions. The intervention targeted poor households with children aged 12 to 24 months at baseline and lasted 18 months.
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Human Capital Development and Parental Investment in India

with Costas Meghir and Emily Nix (June 2015, NBER WP No.21740)

Abstract: We study human development from the early years to adolescence by embedding a structural model within a measurement system for factor models. Our theoretical framework extends in several dimensions the approach taken by Cunha et al (2010). We use flexible functional form assumptions for the distribution of factors and use an instrumental variable approach to take into account the endogeneity of investment. Using data from three waves of two cohorts of Indian Children from the Young Lives Survey, we estimate the production function for two dimensions of human capital: cognition and health. The richness of the data and the fact that they cover children from the age of 1 until the age of 15 allows us to cover a very long and important interval, which has previously not been investigated in this fashion. We uncover important complementarities, so that the non-linearity of the production function is important. We also show that it is important to take into account the endogeneity of investment.
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– The Effects of the Transition from Home-based Community Nurseries to Childcare Centers on Children in Colombia

with R. Bernal, X. Peña and M. Vera-Hernandez

Abstract: Colombia’s national early childhood strategy launched in 2011 aimed at improving the quality of childcare services offered to socio-economically vulnerable children, and included transferring children from small non-parental family daycare units into large childcare centers in urban areas. This study seeks to understand the effects of this transition on children’s cognitive and socio-emotional development, as well as nutritional and health status, using a cluster-randomized control trial with a sample of 2,767 children between the ages of 6 and 60 months. The results point to improved height for age, a reduction in overweight children, and an increase in the incidence of diarrhea due to the transition. Apart from these, the transition did not have statistically significant effects on most developmental outcomes.
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– Work Pays: Different Benefits of a Workfare Program in Colombia

with Arthur Alik-Lagrange Costas Meghir, Sandra Polana-Reyes and Marcos Vera-Hernandez (available soon)

Abstract: Workfare programs provide a low paid employment guarantee to individuals in selected public works. They are designed to self-select the poor and provide insurance against job losses by informal sector workers at the possible cost of crowding out private labor effort. We analyze the impact of a Colombian workfare program called Job in Action [Empleo en Accin] to shed light on the following issues: (1) whether the program crowds out labor effort by members of the household different from the participant in the particular context of a middle-income economy, (2) whether there are gains in household labor income, but also in consumption, which is important to assess the role of the program as an insurance mechanism and (3) whether there are some gains from participating in the program six months after the program has finished. Our results show no evidence of the program crowding out private labor effort by other household members. In addition, we find that the program had large positive transfer benefits, as the program increased individuals labor income and labor supply in large as well as small municipalities. There is a positive significant impact in small municipalities on consumption which is doubled when focusing only on food consumption. Finally, we do find that the program had a significant positive effect on individuals outcomes as well as on households monthly labor income per capita in small rural municipalities six months after the program ended. We shed light on the potential channels explaining this novel result in the literature on public work schemes.
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Aggregating Elasticities: Intensive and Extensive Margins of Female Labour Supply

with Peter Levell, Hamish Low and Virginia Sanchez-Marcos (June 2015)

Abstract: There is a renewed interest in the size of labour supply elasticities and the discrepancy between micro and macro estimates. Recent contributions have stressed the distinction between changes in labour supply at the extensive and the intensive margin. In this paper, we stress the importance of individual heterogeneity and aggregation problems. At the intensive margins, simple specifications that seem to fit the data give rise to non-linear expressions that do not aggregate in a simple fashion. At the extensive margin, aggregate changes in participation are likely to depend on the cross sectional distribution of state variables when a shock hits and, therefore, are likely to be history dependent. We tackle these aggregation issues directly by specifying a life cycle model to explain female labour supply in the US and estimate its various components. We estimate the parameters of different component of the model. Our results indicate that (i) at the intensive margin, Marshallian and Hicksian elasticities are very heterogeneous and, on average, relatively large; (ii) Frisch elasticities are, as implied by the theory, even larger; (iii) aggregate labour supply elasticities seem to vary over the business cycle, being larger during recessions.
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Long Term Impacts of Vocational Training: Experimental Evidence for Colombia

with Arlen Guarn, Carlos Medina and Costas Meghir (June 2015)

Abstract: We use experimental data on a training program implemented in 2005 in Colombia. We match the experimental survey data collected for evaluation purposes with administrative data and find that, up to ten years later, the JeA program had a positive and significant effect on the probability to work in the formal sector. Applicants in the treatment group also contributed more months to social security and were more likely to work for a large firm. Earnings of treated applicants were 11.8% higher in the whole sample, and they made larger contributions to social security. Consistently with the findings of the short term evaluation, we find that most of the impact on formal earnings is obtained through higher participation in the formal sector. We compute non-parametric bounds for the impact of the program on various percentiles of the earnings distribution and we find some suggestive evidence that for women the program might have also increased productivity. The evidence however is not precise enough to obtain significant lower bounds for these effects. Throughout the analysis we compute p-values corrected for multiple hypotheses testing. We also find that for the whole sample of applicants, those in the treatment group have 0.315 more years of education, and have a probability of graduating from high school 10 percent higher than the control group. We find no significant effect on the probability of attending college or any school program, nor on fertility decisions, marital status or some dimensions of assortative mating. Among applicants matching to the census of the poorest population, we find that beneficiaries are more likely to participate in the labor market, to be employed, and to be enrolled in a private health insurance at the time of the survey. Finally, we find that the benefits of the JeA program are higher than it costs, leading to an internal rate of return of at least 22.1 percent. On the whole, the program was a cost-effective alternative, worth to consider to bridging the transit of youths from the informal to the formal sector in the future.
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Measuring and Changing Control: Womens Empowerment and Targeted Transfers

with Ingvild Almas, Alex Armand and Pedro Carneiro (October 2015)

Abstract: This paper studies how targeted cash transfers to women affect their empowerment. We use a novel identification strategy to measure women’s willingness to pay to receive cash transfers instead of their partner receiving it. We apply this among women living in poor households in urban Macedonia. We match  experimental data with a unique policy intervention (CCT) in Macedonia offering poor households cash transfers conditional on having their children attending secondary school. The program  randomized whether the transfer was offered to household heads or mothers at municipality level, providing us with an exogenous source of variation in (offered) transfers. We show that women who were offered the transfer reveal a lower willingness to pay, and we show that this is in line with theoretical predictions.
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Non-Linear Pricing in Village Economies

with Elena Pastorino (November 2015)

Abstract: We propose a model of price discrimination that accounts for the nonlinearity of unit prices of basic food items in developing countries. We model consumers subsistence constraints and allow consumers to differ in their marginal willingness and absolute ability to pay for a good. We also incorporate outside options from purchasing a good that depend on consumers preferences for the good, like self-production or access to other markets. We obtain a simple characterization of optimal nonlinear pricing and show that nonlinear pricing leads to higher levels of consumption, lower marginal prices, and higher consumer surplus than implied by the standard nonlinear pricing model. We prove that a multiplicative utility version our model is nonparametrically identified under common assumptions, derive nonparametric and semi- parametric estimators of the models primitives, and develop a test that formally allows to distinguish between our model and the standard model. These estimators, as well as the test we propose, can be easily implemented using individual-level data commonly available for beneficiaries of conditional cash transfer programs in developing countries. We find that the model well accounts for the data and that at the estimated primitives, nonlinear pricing especially benefits consumers who purchase intermediate to large quantities compared to linear pricing. We show that failure to account for the endogeneity of prices in the presence of heterogeneous constraints among consumers can lead to an incorrect assessment of the impact of common policies, like cash transfers, that affect households ability to pay. When sellers have market power, such policies effectively increase sellers ability to price discriminate and may thus give rise to asymmetric price changes for low and high quantities demanded, thereby exacerbating the consumption distortions typically associated with nonlinear pricing. These results confirm the importance of incorporating our proposed extensions of the standard nonlinear pricing model to evaluate the distributional effects of nonlinear pricing.
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– Microcredit Contracts and Risk Diversification

with Britta Augsburg and Ralph de Haas (available soon)

Abstract: In this paper, we study theoretically and empirically the demand for microfinance loans under different contract arrangements and different environments. In particular, we compare loans with joint liability to loans with group liability. With a simple theoretical model, we show that the demand for group liability loans can be larger than that for individual liability loans in an environment in which risk averse customers value the long run relationship with the microfinance institution. Joint liability loans might constitute a way to diversify risk. We also show that the demand for loans depend negatively on the riskness of the projects. Empirically, using data from a randomized controlled trial from Mongolia, we show that the predictions of the model hold true in the data. We use innovative data on subjective expectations about the riskness of projects and show that the subjective riskness of projects does affect negatively the demand for loans but the effect is muted in villages where group loans are available, confirming the insurance role of joint liability loans.
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Insurance in Extended Family Networks

with Costas Meghir and Corina Mommaerts (March 2015, NBER WP No.21059)

Abstract: This paper analyzes the extent to which members of an extended family network insure each another against income shocks. We develop a model of intertemporal consumption that decomposes income shocks and insurance parameters into within-family and between-family components and generates a test of within-family partial insurance. To identify the model, we derive covariance restrictions between income and consumption across family members and over time. We use recent income and consumption panel data from the PSID and exploit the intergenerational structure of the data to estimate the parameters of the model.
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Global demographic trends, capital mobility, saving and consumption in Latin America and Caribbean

with Andrea Bonfatti, Sagiri Kitao and Guglielmo Weber (March 2015)

Abstract: In this paper we study the effect of demographic transitions on the economy of Latin America and Caribbean (LAC). We build a model of multi- regions of the world and derive the path of macroeconomic variables including aggregate output, capital, labor and saving rate, as the economies face a rapid shift in the demographics. The timing and the extent of the demographic transition differ across regions. We simulate the model in both closed economy and open economy assumptions to quantify the roles played by the factor mobility across regions in shaping capital accumulation and equilibrium factor prices.
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Mortality, Permanent Income and Inequality

with Torben Nielen (May 2014)

Abstract: Using full-population register data from Denmark, this study shows that estimates of the economic gradient in mortality depends on the specific measure of economic resources used, where we investigate permanent income, annual income or financial and housing wealth. Our favorite measure is what we call ‘Permanent income’, that is the average level of income over a long interval. We find that when using annual income or current wealth, the gradient is overestimated, unless one controls for a number of additional variables, such as education, civil status and initial health. In the last part of the paper, we compare the results from Denmark to results from the UK. Although the countries are very different in terms of inequality, the estimates of the gradient we find are very similar, suggesting that differential levels of resources (including information), rather than inequality itself, determine the gradient in survival and mortality.
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Conditional cash transfers, women and the demand for food

with Valérie Lechene (September 2010)

Abstract: We examine the effect of large cash transfers on the consumption of food by poor households in rural Mexico. The transfers represent 20% of household income on average, and yet, the budget share of food is unchanged following receipt of this money. This is an important puzzle to solve, particularly so in the context of a social welfare programme designed in part to improve nutrition of individuals in the poorest households. We estimate an Engel curve for food. We rule out price increases, changes in the quality of food consumed and homotheticity of preferences as explanations for this puzzle. We also show that food is a necessity, with a strong negative effect of income on the food budget share. The decrease in food budget share caused by the large increase in income is cancelled by some other relevant aspect of the programme so that the net effect is nil. We argue that the program has not changed preferences and that there is no labelling of money. We propose that the key to the puzzle resides in the fact that the transfer is put in the hands of women and that the change in control over household resources is what leads to the observed changes in behaviour.
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– Cultural adaptation of a neurobiologically-informed intervention in local and international contexts

with E. Paculak et al. (New Developments for Child & Adolescent Development, forthcoming)

Abstract: NA
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– Measuring and Changing Control: Women’s Empowerment and Targeted Transfers

with I.Almås, A. Armand and P. Carneiro (Economic Journal, forthcoming)

Abstract: This paper suggests, uses, and evaluates a novel identification strategy to measure power in the household. Our strategy is to elicit women’s willingness to pay to receive a cash transfer instead of their spouse receiving the same transfer. We selected participants from a sample of women who had already participated in a unique policy intervention in Macedonia offering poor households cash transfers conditional on having their children attending secondary school. The program randomized whether the cash transfers were  offered to household heads (generally a male) or mothers, at municipality level. We show that women who were offered the transfer on average have stronger measured empowerment, and IV estimations confirm that targeted transfers empower women according to our measure. We further show that this elicitation is in line with theoretical predictions from standard models of household decision making.
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Holy Cows or Cash Cows? The Economic Return to Livestock in Rural India

with Britta Augsburg (Economic Development & Cultural Change, forthcoming)

Abstract: This paper revisits recent claims that poor households owning cattle in developing countries settings do not behave according to the tenets of capitalism. We point out that the discussion was based on evidence from one single year only, while cows and buffalos are assets whose return varies through time. In drought years, when fodder is scarce and more expensive, milk production is lower and profits are low. In nondrought years, when fodder is abundant and cheaper, milk production is higher and profits can be considerably higher. Therefore, the return on cows and buffalos, like that of many stocks traded on Wall Street, is positive in some years and negative in others. The fact that in a given year the observed return on a risky asset is negative could certainly not be used as a contradiction of one of the basic tenets of capitalism. We report evidence from 3 years of data on the return on cows and buffalos in the district of Anantapur and show that in one of the 3 years returns are very high, while in drought years they are predominantly negative.
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Concurrent Validity and Feasibility of Short Tests Currently Used to Measure Early Childhood Development in Large Scale Studies

with M.Rubio-Codina, C. Araujo, P. Muñoz and S. Grantham-McGregor (PLoS ONE, Vol. 11(8), August 2017)

Abstract: In low- and middle-income countries (LIMCs), measuring early childhood development (ECD) with standard tests in large scale surveys and evaluations of interventions is difficult and expensive. Multi-dimensional screeners and single-domain tests (‘short tests’) are frequently used as alternatives. However, their validity in these circumstances is unknown. We examined the feasibility, reliability, and concurrent validity of three multi-dimensional screeners (Ages and Stages Questionnaires (ASQ-3), Denver Developmental Screening Test (Denver-II), Battelle Developmental Inventory screener (BDI-2)) and two single-domain tests (MacArthur-Bates Short-Forms (SFI and SFII), WHO Motor Milestones (WHO-Motor)) in 1,311 children 6–42 months in Bogota, Colombia. The scores were compared with those on the Bayley Scales of Infant and Toddler Development (Bayley-III), taken as the ‘gold standard’. The Bayley-III was given at a center by psychologists; whereas the short tests were administered in the home by interviewers, as in a survey setting. Findings indicated good internal validity of all short tests except the ASQ-3. The BDI-2 took long to administer and was expensive, while the single-domain tests were quickest and cheapest and the Denver-II and ASQ-3 were intermediate. Concurrent validity of the multi-dimensional tests’ cognitive, language, and fine motor scales with the corresponding Bayley-III scale was low below 19 months. However, it increased with age, becoming moderate-to-high over 30 months. In contrast, gross motor scales’ concurrence was high under 19 months and then decreased. Of the single-domain tests, the WHO-Motor had high validity with gross motor under 16 months, and the SFI and SFII expressive scales showed moderate correlations with language under 30 months. Overall, the Denver-II was the most feasible and valid multi-dimensional test and the ASQ-3 performed poorly under 31 months. By domain, gross motor development had the highest concurrence below 19 months, and language above. Predictive validity investigation is needed to further guide the choice of instruments for large scale studies.
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Education Choices and Returns on the Labour and Marriage Markets: Evidence from Data on Subjective Expectations

with Katja Kaufmann (Journal of Economic Behaviour & Organization, Vol. 140, August 2017, pp35-55)

Abstract: In this paper we analyze the role of expected labor and marriage market returns as determinants of the college enrollment decisions of Mexican high school graduates. Moreover, we investigate whether the (relative) weights of these factors differ by gender. We use data on individuals’ expectations regarding future labor market outcomes which we directly elicited from the youths, and two different measures of marriage market returns. First, marriage market returns are proxied by the (net-)supply of potential partners in the youths’ local marriage markets. Second, we use data which elicits youths’ beliefs about their future spouse’s earnings conditional on their own education level. We find that labor market as well as marriage market returns are important determinants of the college enrollment decision. However, boys’ and girls’ preferences differ in terms of the relative role of the two determinants, in that the relative weight of labor market versus marriage market returns is larger for boys than for girls.
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– Vocational Training for Disadvantaged Youth in Colombia: A Long-Term Follow-Up

with Arlen Guarín, Carlos Medina, and Costas Meghir (American Economic Journal: Applied Economics, Vol.9(2), April 2017, pp131-43)

Abstract: We evaluate the long-term impacts of a randomized Colombian training and job placement program. Following the large short-term effects, we now find that the program effects persist, increasing formal participation and earnings contributions to social security and working in larger firms. By using a large administrative source we are also able to establish that the program improved both male and female labor market outcomes by a similar amount–a result that was not apparent with the smaller evaluation sample. The results point to a cost-effective approach to reducing informality and improving labor market outcomes in the long run.
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Human capital growth and poverty: Evidence from Ethiopia and Peru

with Costas Meghir, Emily Nix, and Francesca Salvati (Review of Economic Dynamics, Vol. 25, April 2017, pp234-259)

Abstract: In this paper we use high quality data from two developing countries, Ethiopia and Peru, to estimate the production functions of human capital from age 1 to age 15. We characterize the nature of persistence and dynamic complementarities between two components of human capital: health and cognition. We also explore the implications of different functional form assumptions for the production functions. We find that more able and higher income parents invest more, particularly at younger ages when investments have the greatest impacts. These differences in investments by parental income lead to large gaps in inequality by age 8 that persist through age 15.
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Why is Multiple Micronutrient Powder Ineffective at Reducing Childhood Anaemia in Colombia? Evidence from a Randomised Controlled Trial

with Alison Andrew, Emla Fitzsimons and Marta Rubio-Codina (SSM – Population Health, Vol. 2, December 2016,  pp95-104)

Abstract: In Colombia’s bottom socio-economic strata, 46.6% of children under two are anaemic. A prevalence of above 20% falls within the WHO guidelines for daily supplementation with multiple micronutrient powder (MNP). To evaluate the effect of daily MNP supplementation on anaemia amongst Colombian children aged 12–24 months we ran a cluster RCT (n=1440). In previous work, we found the intervention had no impact on haemoglobin or anaemia in this population. In this current paper, we investigate this null result and find it cannot be explained by an underpowered study design, inaccurate measurements, low adoption of and compliance with the intervention, or crowding out through dietary substitution. We conclude that our intervention was ineffective at reducing rates of childhood anaemia because MNP itself was inefficacious in our population, rather than poor implementation of or adherence to the planned intervention. Further analysis of our data and secondary data suggests that the evolution with age of childhood anaemia in Colombia, and its causes, appear different from those in settings where MNP has been effective. Firstly, rates of anaemia peak at much earlier ages and then fall rapidly. Secondly, anaemia that remains after the first year of life is relatively, and increasingly as children get older, unrelated to iron deficiency. We suggest that factors during gestation, birth, breastfeeding and early weaning may be important in explaining very high rates of anaemia in early infancy. However, the adverse effects of these factors appear to be largely mitigated by the introduction of solid foods that often include meat. This renders population wide MNP supplementation, provided after a diet of solid foods has become established, an ineffective instrument with which to target Colombia’s childhood anaemia problem.
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Mediating Pathways in the Socio-economic Gradient of Child Development: Evidence from Children 6–42 Months in Bogota

with M. Rubio-Codina and S. Grantham McGregor (International Journal of Behavioral Development, Vol. 40(6), June 2016, pp483-491)

Abstract: Research has previously shown a gap of near 0.5 of a standard deviation (SD) in cognition and language development between the top and bottom household wealth quartile in children aged 6–42 months in a large representative sample of low- and middle-income families in Bogota, using the Bayley Scales of Infant and Toddler Development. The gaps in fine motor and socio-emotional development were about half that size. Developmental deficits increased with age. The current study explored the associations amongst child development, household socio-economic status (SES), and a set of potential mediating variables—parental characteristics, child biomedical factors, and the quality of the home environment—in this sample. We ran mediation tests to quantify the contribution of these variables to the SES gap, and explored the role of age as a moderator. Parental education, particularly maternal education, and the quality of the home environment mediated the SES gap in all outcomes examined. Height-for-age mediated a small amount of the deficit in language scales only. More educated mothers provided better home stimulation than less educated mothers and the home environment partly mediated the effect of maternal education. These results suggested that in interventions aimed at promoting child development, those focusing on the quality of the home environment should be effective.
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Challenges to promoting social inclusion of the extreme poor: Evidence from a large scale experiment in Colombia

with Laura Abramosky, Kay Barron, Pedro Carneiro and George Stoye (forthcoming in Economia, Journal of LACEA)

Abstract: We evaluate the large scale pilot of an innovative and major welfare intervention in Colom- bia, which combines homes visits by trained social workers to households in extreme poverty with preferential access to social programs. We use a randomized control trial and a very rich dataset collected as part of the evaluation to identify program impacts on the knowledge and take-up of social programs and the labor supply of targeted households. We find no consistent impact of the program on these outcomes, possibly because the way the pilot was implemented resulted in very light treatment in terms of home visits. Importantly, administrative data in- dicates that the program has been rolled out nationally in a very similar fashion, suggesting that this major national program is likely to fail in making a significant contribution to re- ducing extreme poverty. We suggest that the program should undergo substantial reforms, which in turn should be evaluated.
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Consumption Inequality

with Luigi Pistaferri (Journal of Economic Perspectives, Vol. 30(2), pp3-28)

Abstract: In this essay, we discuss the importance of consumption inequality in the debate concerning the measurement of disparities in economic well-being. We summarize the advantages and disadvantages of using consumption as opposed to income for measuring trends in economic well-being. We critically evaluate the available evidence on these trends, and in particular discuss how the literature has evolved in its assessment of whether consumption inequality has grown as much as or less than income inequality. We provide some novel evidence on three relatively unexplored themes: inequality in different spending components, inequality in leisure time, and intergenerational consumption mobility.
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Subjective Expectations and Income processes in rural India

with B. Augsburg (Economica, Vol. 83(331), July 2016, pp416-442)

Abstract: This paper uses unique primary data on directly elicited individual subjective expectations to analyse and characterize the process that generates the income of poor, rural Indian households. We validate and use responses to subjective expectations questions and a parametric assumption to fit a household-specific probability distribution for future income. Combining computed moments from this distribution with data for actual current income, we specify and estimate a dynamic model of household income. We find that our households face a very persistent income process. Our paper is one of the first that uses subjective expectations data to model income processes.
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The Determinants of Human Capital Formation During the Early Years of Life: Theory Measurement and Policies

(Journal of the European Economic Association, Vol 13(6), December 2015, pp949-997)

Abstract: This paper is based on my presidential address for the European Economic Association meetings held in Toulouse in August 2014. In it, 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.
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Frank Ramsey’s A Mathematical Theory of Saving

(Economic Journal, Vol. 125(583), March 2015, pp269-294)

Abstract: In 1928, Frank Ramsey, a British mathematician and philosopher, at the time aged only 25, published an article (Ramsey, 1928) whose content was utterly innovative and sowed the seeds of many subsequent developments. Beside the theory of optimal growth, as developed in Cass (1965) and Koopmans (1965), one could argue that the essence of several subsequent influential theories, such as the permanent income/life cycle theory of consumption to model individual saving choices, were already contained in that seminal article.

In this note, I first summarise the content of Ramsey’s paper and then relate it to subsequent developments in economics. Before starting, however, I cannot help mentioning the modernity and originality one perceives in Ramsey’s writings when going through the original texts. His papers and contributions are astonishingly ahead of their time. This is true for his article on optimal taxation, (Ramsey, 1927), which is reviewed elsewhere in this issue and for his article on ‘Truth and probability’ (Ramsey, 1926), in which he discusses choices under uncertainty decades ahead of Von Neumann and Morgenstern (1944) and even proposes an experimental way to disentangle preferences and probability assessments from choices. In this note, I discuss how the article on saving and optimal growth anticipated several branches of the literature that followed in subsequent decades. The treatment of individual consumption and saving choices, for instance, is a very modern one. Interestingly, Ramsey’s article refers explicitly to conversations with John Maynard Keynes, who was Ramsey’s colleague at Cambridge and the Economic Journal‘s editor, in formulating part of the main proposition. And yet, in his General Theory, Keynes (1936) used a much more simplistic and stylised theory of consumption, which had profound implications for the working of his model of the macroeconomy.
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Building social capital: conditional cash transfers and cooperation

with L. Pellerano and S. Polania-Reyes (Journal of Economic Behavior and Organization, Vol. 118, October 2015, pp22-39)

Abstract: Many conditional cash transfer (CCT) programs have important social components and, therefore, can have an effect on social capital. In 2007, we conducted a field experiment with 1451 subjects in Cartagena, Colombia. We interpret the behavior in the game as a measure of what in the literature has been called social capital. We played the game in two similar and adjacent neighborhoods. The ‘treatment’ neighborhood, Pozón, had been targeted for over 2 years by a CCT program, Familias en Acción; the ‘control’ neighborhood, Ciénaga, had not. In 2008, with the program being implemented in both neighborhoods, we played the same public goods game, and were therefore able to implement a difference in differences strategy to estimate the impact of the CCT on our measure of social capital. In 2007, the level of cooperation we observed in the treatment neighborhood was considerably higher than that in the control one. Although similar in many dimensions, the two groups turned out to be significantly different in some observable variables; the positive result was robust to controls for these differences. In 2008, we found that the level of cooperation was statistically identical across the two neighborhoods, and similar to the levels observed in 2007 in the treatment one. We conclude that the CCT program did improve cooperation. In analyzing the effect of the CCT on cooperation we also look at other (individual and group) determinants of individual behavior in the game, and we compare our measure based on behavior in the game to more traditional measures of social capital used in the literature that we collected in a context-specific survey.
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The Socio-Economic Gradient of Child Development: Cross-Sectional Evidence from Children 6-42 months in Bogota

with Marta Rubio-Codina, Costas Meghir, Natalia Varela, and Sally Grantham-McGregor (Journal of Human Resources, Vol. 50(2), Spring 2015, pp464-483)

Abstract: We study the socioeconomic gradient of child development on a sample of low- and middle-income children aged 6–42 months in Bogota using the Bayley Scales of Infant and Toddler Development. We find an average difference of 0.53, 0.42, and 0.49 standard deviations (SD) in cognition, receptive, and expressive language respectively, between children in the top and bottom quartile of the wealth distribution. These gaps increase substantially to 0.81 SD (cognition), 0.76 SD (receptive language), and 0.68 SD (expressive language) for children aged 31–42 months. These robust findings can inform the design and targeting of interventions promoting early childhood development.
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Should Cash Transfers Be Conditional? Conditionality, Preventive Care, and Health Outcomes

with Veruska Oppedisano and Marcos Vera-Hernandez (AEJ: Applied, Vol. 7(2), April 2015, pp35-52)

Abstract: We study a Conditional Cash Transfer program in which the cash transfers to the mother only depend on the fulfillment of the national preventive visit schedule by her children born before she registered in the program. We estimate that preventive visits of children born after the mother registered in the program are 50 percent lower because they are excluded from the conditionality requirement. Using the same variation, we also show that attendance to preventive care improves children health.
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The Impacts of Microfinance: Evidence from Joint-Liability Lending in Mongolia

with Britta Augsburg, Ralph De Haas, Emla Fitzsimons and Heike Hamgart (American Economic Journal: Applied Economics, Vol. 7(1), January 2015, pp90-122)

Abstract: We present evidence from a randomized field experiment in rural Mongolia to assess the poverty impacts of a joint-liability microcredit program targeted at women. We find a positive impact of access to group loans on female entrepreneurship and household food consumption but not on total working hours or income in the household. A simultaneously introduced individual-liability microcredit program delivers no significant poverty impacts. Additional results on informal transfers to families and friends suggest that joint liability may deter borrowers from using loans for noninvestment purposes with stronger impacts as a result. We find no difference in repayment rates between both types of microcredit.
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Modelling Movements in Individual Consumption: A Time Series Analysis of Grouped Data

with M Borella (International Economic Review, Vol. 55(4), November 2014, pp959-991)

Abstract: We characterize the time-series properties of group-level consumption, income, and interest rates using microdata. We relate the coefficients of moving average representations to structural parameters of theoretical models of consumption behavior. Using long time series of cross sections to construct synthetic panel data for the United Kingdom, we find that for high-educated individuals the Euler equation restrictions are not rejected, the elasticity of intertemporal substitution is higher than one, and there is evidence of “excess smoothness” of consumption. Low-educated individuals, conversely, exhibit excess sensitivity of consumption to past income, and the elasticity of intertemporal substitution is not statistically different from zero.
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Cognitive Deficit and poverty in the first five years of childhood in Bangladesh

with J Hamadani, F. Tofail, S. Huda, D. Alam, D. Ridout, and S. Grantham-McGregor (Pediatrics, Vol. 134(4), October 2014)

Abstract: We aimed to determine the timing and size of the cognitive deficit associated with poverty in the first 5 years of life and to examine the role of parental characteristics, pre- and postnatal growth, and stimulation in the home in Bangladeshi children. We hypothesized that the effect of poverty on cognition begins in infancy and is mainly mediated by these factors. We enrolled 2853 singletons, a subsample from a pregnancy supplementation trial in a poor rural area. We assessed mental development at 7, 18, and 64 months; anthropometry at birth, 12, 24, and 64 months; home stimulation at 18 and 64 months; and family’s socioeconomic background. In multiple regression analyses, we examined the effect of poverty at birth on IQ at 64 months and the extent that other factors mediated the effect. A mean cognitive deficit of 0.2 (95% confidence interval –0.4 to –0.02) z scores between the first and fifth wealth quintiles was apparent at 7 months and increased to 1.2 (95% confidence interval –1.3 to –1.0) z scores of IQ by 64 months. Parental education, pre- and postnatal growth in length, and home stimulation mediated 86% of the effects of poverty on IQ and had independent effects. Growth in the first 2 years had larger effects than later growth. Home stimulation had effects throughout the period. Effects of poverty on children’s cognition are mostly mediated through parental education, birth size, growth in the first 24 months, and home stimulation in the first 5 years.
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Admixture in Latin America: Geographic Structure, Phenotypic Diversity and Self-Perception of Ancestry Based on 7,342 Individuals

with A. Ruiz Linares et al. (PLOS Genetics, Vol. 10(9), September 2014)

Abstract: The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.
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Using the infrastructure of a conditional cash transfer programme to deliver a scalable integrated early child development programme in Colombia: A cluster randomised controlled trial

with C. Fernndez, E. Fitzsimons, S. M Grantham-McGregor, C. Meghir and M. Rubio-Codina (British Medical Journal, 349:g5785, September 2014)

Objective To assess the effectiveness of an integrated early child development intervention, combining stimulation and micronutrient supplementation and delivered on a large scale in Colombia, for children’s development, growth, and hemoglobin levels.

Design Cluster randomized controlled trial, using a 2×2 factorial design, with municipalities assigned to one of four groups: psychosocial stimulation, micronutrient supplementation, combined intervention, or control.

Setting 96 municipalities in Colombia, located across eight of its 32 departments.

Participants 1420 children aged 12-24 months and their primary carers.

Intervention Psychosocial stimulation (weekly home visits with play demonstrations), micronutrient sprinkles given daily, and both combined. All delivered by female community leaders for 18 months.

Main outcome measures Cognitive, receptive and expressive language, and fine and gross motor scores on the Bayley scales of infant development-III; height, weight, and hemoglobin levels measured at the baseline and end of intervention.

Results Stimulation improved cognitive scores (adjusted for age, sex, testers, and baseline levels of outcomes) by 0.26 of a standard deviation (P=0.002). Stimulation also increased receptive language by 0.22 of a standard deviation (P=0.032). Micronutrient supplementation had no significant effect on any outcome and there was no interaction between the interventions. No intervention affected height, weight, or hemoglobin levels.

Conclusions Using the infrastructure of a national welfare program we implemented the integrated early child development intervention on a large scale and showed its potential for improving children’s cognitive development. We found no effect of supplementation on developmental or health outcomes. Moreover, supplementation did not interact with stimulation. The implementation model for delivering stimulation suggests that it may serve as a promising blueprint for future policy on early childhood development.

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Consumption Inequality over the Last Half Century: Some Evidence Using the New PSID Consumption Measure

with L Pistaferri (American Economic Review, Volume 104, Number 5, May 2014, pp122-126)

Abstract: This paper contributes to the debate regarding trends in consumption inequality in the United States. We present a new measure of consumption inequality based on the redesigned 1999–2011 PSID. We impute consumption to the families observed before 1999 using the more comprehensive consumption data available from 1999 onward. One advantage of this procedure is in sample verification of the quality of the imputation procedure; another is that it yields a long time series (1967–2010). Consumption inequality was stable in the 1970s, as was income inequality. It increased significantly after 1980. The Great Recession was associated with a decline in consumption inequality.
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Efficient responses to targeted transfers

with V. Lechene (Journal of Political Economy, Vol. 122(1), February 2014, pp178-222)

Abstract: We estimate and test the restrictions of a collective model of household consumption, using z-conditional demands, in the context of a large conditional cash transfer program in rural Mexico. The model can explain the impacts of the program on the structure of food consumption. We use two plausible and novel distribution factors: the random allocation of a cash transfer to women and the relative size and wealth of the husband’s and wife’s family networks. Our structure does better at predicting the effect of exogenous increases in household income than an alternative, unitary, structure. We cannot reject efficiency of household decisions.
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Education Choices and Returns to Schooling: Intra-household Decision Making, Gender and Subjective Expectations

with Katja Kaufmann (Journal of Development Economics, Vol. 109(C), July 2014, pp203-216)

Abstract: In this paper we investigate the role of expected returns to schooling and of perceived risks (of unemployment and  earnings) as determinants of schooling decisions. Moreover, our data also allow us to shed light on the intrahousehold decision making process by analyzing whose expectations matter in schooling decisions, youths’ or parents’, and whether this depends on the age and gender of the youth. In particular, we use Mexican data that contain labor market expectations of both parents and youths. We  find that expected returns and risk perceptions are important determinants of schooling decisions. Regarding youths’ role in the decision-making process, our results show that while both boys  and girls expect high returns to schooling, only boys’ expectations matter in the decision, but not the ones of girls. Parents’ role depends on gender and age of the youths.
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Community Nurseries and the Nutritional Status of Poor Children. Evidence from Colombia

with V di Maro and M Vera-Hernandez (Economic Journal, Vol 123 (9), September 2013, pp1025-1058)

Abstract: We use two different data sets and three different instruments to estimate the impact of a long-established pre-school nursery programme on children’s nutritional status. We use variables related to cost (fee, distance to the nursery) and programme availability (capacity of the programme in the town) as instruments. One of our data sets is representative of very poor individuals living in rural areas of Colombia, while the other focuses in urban areas and includes individuals relatively less poor. We find that programme participation increases children’s height, with the size of the effect being consistent across the three instruments and the two data sets.
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The effect of increases in food prices on consumption and welfare in rural Mexico

with V. DiMaro, V. Lechene and D. Phillips (Journal of Development Economics, Vol. 104(C), February 2013, pp136-151)

Abstract: This paper presents an analysis of the welfare consequences of recent increases in food prices in Mexico using micro-level data. We estimate a QUAIDS model of demand for food, using data collected to evaluate the conditional cash transfer program Oportunidades. We show how the poor have been affected by the recent increases and changes in relative prices of foods. We also show how a conditional cash transfer program provides a means of alleviating the problem of increasing staple prices, and simulate the impact of such a policy on household welfare and consumer demand. We contrast this policy with alternative policy responses, such as price subsidies, which distort relative prices and are less well-targeted.
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The demand for food of poor urban Mexican households: Understanding policy impacts using structural models

with M Angelucci (American Economic Journal: Economic Policy, Vol 5(1), February 2013, pp146-78)

Abstract: We use Oportunidades, a conditional cash transfer to women, to show that standard demand models do not represent the sample’s behavior: Oportunidades increases eligible households’ food budget shares, despite food being a necessity; demand for food and high-protein food changes over time only in treatment areas; the treatment effects on food and high-protein food consumption are larger than the prediction from the Engel curves at baseline; and the curves do not change in eligible households with high baseline bargaining power for the transfer recipient. Thus, handing transfers to women is a likely determinant of the observed nutritional changes.
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The Impact of Oportunidades on Consumption, Savings and Transfers

with M. Angelucci and V. DiMaro (Fiscal Studies, Vol. 33(3), September 2012, pp305-334)

Abstract: In this paper, we estimate the effect of the Mexican conditional cash transfer programme, Oportunidades, on transfers, savings and consumption for treated households. We find positive effects on consumption of non-durable and durable goods, an increase in savings coupled with a drop in the number and values of loans, and a reduction of in-kind transfers received by households in treatment areas. These results are consistent with the existing evidence that conditional cash transfer programmes have beneficial effects in both the short and medium term, but that they partly crowd out private transfers.
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Risk Pooling, Risk Preferences, and Social Networks

with A Barr, JC Cardenas, G Genicot and C Meghir (American Economic Journal: Applied Economics, Vol. 4(2), April 2012, pp134–67)

Abstract: Using data from an experiment conducted in 70 Colombian communities, we investigate who pools risk with whom when trust is crucial for enforcing risk pooling arrangements. We explore the roles played by risk attitudes and social networks. Both empirically and theoretically, we find that close friends and relatives group assortatively on risk attitudes and are more likely to join the same risk pooling group, while unfamiliar participants group less and rarely assort. These findings indicate that where there are advantages to grouping assortatively on risk attitudes those advantages may be inaccessible when trust is absent or low.
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Food and Cash Transfers: Evidence from Colombia

with E. Battistin and A. Mesnard (Economic Journal , Vol. 122(559), March 2012, pp92-124)

Abstract: We study food Engel curves amongst the poor population targeted by a conditional cash transfer programme in Colombia. After controlling for the endogeneity of total consumption and for the price variability across villages, our estimates imply that an increase in consumption by 10% would lead to a decrease of 1% in the share of food. However, quasi-experimental estimates of the impact of the programme show that the share of food increases. This result is not inconsistent with the hypothesis that the programme could increase the bargaining power of women, inducing a more than proportional increase in food consumption.
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Modelling the demand for housing over the life cycle

with R. Bottazzi, H. Low, L. Neisham and M. Wakefield (Review of Economic Dynamics, Vol. 15(1), January 2012, pp1-18)

Abstract: We model individual demand for housing over the life cycle, and show the aggregate implications of this behaviour. Individuals delay purchasing their first home when incomes are low or uncertain. Higher house prices lead households to downsize, rather than to stop being owners. Fixed costs (property transactions taxes) have important impacts on welfare (a wealth effect) and house purchase decisions (substitution effect). In aggregate, positive house price shocks lead to consumption booms among the old but falls in consumption for the young, and reduced housing demand; positive income shocks lead to consumption booms among the young and increased housing demand.
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Education Choices in Mexico: Using a Structural Model and a Randomized Experiment to Evaluate PROGRESA

with C. Meghir and A. Santiago (The Review of Economic Studies, Vol. 79 (1), January 2012, pp37-66)

Abstract: In this paper we use an economic model to analyse data from a major randomised social experiment, namely  PROGRESA in Mexico, and to evaluate its impact on school participation. We show the usefulness of using experimental data to estimate a structural economic model as well as the importance of a  structural model in interpreting experimental results. The availability of the experiment also allow us to estimate the program’s general equilibrium effects, which we then incorporate into out simulations. Our main findings are : (i) the program’s grant has a much stronger impact on school enrolment than an equivalent reduction in child wages; (ii) the program has a positive effect on the enrollment of children, especially after primary school; this result is well replicated by the parsimonious structural model; (iii) there are sizeable effects of the program on child wages, which, however, reduce the effectiveness of the program only marginally; (iv) a revenue neutral change in the program that would increase the grant for secondary school children while eliminating for the primary school children would have a substantially larger effect on enrollment of the latter, while having minor effects on the former.
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Behind the scenes: experience managing and conducting large impact evaluations in Colombia

with Bertha Briceo and Laura Cuesta (Journal of Development Effectiveness, Vol. 3(4), December 2011, pp470-501)

Abstract: As more resources are being allocated to impact evaluation of development programmes, the need to map out the utilisation and influence of evaluations has been increasingly highlighted. This paper aims at filling this gap by describing and discussing experiences from four large impact evaluations in Colombia on case- study basis. On the basis of learning from our prior experience in both managing and conducting impact evaluations, desk review of available documentation from the monitoring and evaluation system, and structured interviews with government actors, evaluators and programme managers, we benchmark each evaluation against 11 standards of quality. From this benchmarking exercise, we derive five key lessons for conducting high-quality and influential impact evaluations: investing in preparation of good terms of reference and identification of evaluation questions; choosing the best methodological approach to address the evaluation questions; adopting mechanisms to ensure evaluation quality; laying out the incentives for involved parties in order to foster evaluation buy-in; and carrying out a plan for quality dissemination.
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The impact of cash transfers to poor women in Colombia on BMI and obesity: prospective cohort study

with I Forde, T. Chandola, S. Garcia and M. Marmot (International Journal of Obesity, Vol. 36(9), December 2011, pp1209-1214)

Introduction Prevalence of obesity is rising in Latin America and increasingly affecting socially disadvantaged groups, particularly women. Conditional cash transfers are recently established welfare interventions in the region. One, Familias en Accion, transfers ?20% of average monthly income to women in Colombia’s poorest families. Previous work has found that families buy more food as a result. We tested the hypothesis that participation in Familias would be associated with increasing body mass index (BMI) in participating women.

Methods Women from participating areas and control areas (matched on environmental and socioeconomic criteria) were surveyed in 2002 and 2006. Pregnant, breast-feeding or women aged <18 or with BMI <18.5?kg?m(-2) were excluded. The sample comprises 835 women from control and 1238 from treatment areas. Because some treatment areas started Familias shortly before baseline data collection, a dummy variable was created that identified exposure independent of time point or area. Follow-up was 61.5%. BMI was measured by trained personnel using standardized techniques. Overweight was defined as BMI ? 25?kg?m(-2) and obesity as ? 30?kg?m(-2). The effect of Familias was estimated using linear regression (or logistic regression for dichotomous outcomes) in a double-difference technique, controlling for several individual, household and area characteristics, including parity and baseline BMI, using robust standard-errors clustered at area-level in an intention-to-treat analysis.

Results At baseline, women’s mean age was 33.3 years and mean BMI 25.3?kg?m(-2); 12.3% women were obese. After adjustment, exposure to Familias was significantly associated with increased BMI (?=0.25; 95% confidence interval (CI) 0.03, 0.47; P=0.03). Age (?=0.09; 95% CI 0.06, 0.13; P<0.001) and household wealth (?=0.78; 95% CI 0.41, 1.15; P<0.001) were also positively associated with BMI. Familias was also associated with increased odds of obesity (odds ratio (OR)=1.27; 95% CI 1.03, 1.57; P=0.03), as was age (OR=1.04; 95% CI 1.02, 1.06; P=0.001).

Conclusion Conditional cash transfers to poor women in Colombia are independently associated with increasing BMI and obesity risk. Although conditional cash transfers are generally regarded as popular and successful schemes, parallel interventions at individual, household and community level are needed to avoid unanticipated adverse outcomes.

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Changes in Consumption at Retirement

with Emma Aguila and Costas Meghir (Review of Economics and Statistics, Vol. 93(3), August 2011, pp1094-1099)

Abstract: Previous empirical literature has found a sharp decline in consumption during the first years of retirement, implying that individuals do not save enough for their retirement. This phenomenon is called the retirement consumption puzzle. We find no evidence of the retirement consumption puzzle using panel data from 1980 to 2000. Consumption is defined as nondurable expenditure, a more comprehensive measure than only food used in many of the previous studies. We find that food expenditure declines at retirement, which is consistent with previous studies.
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Subsidizing Vocational Training for Disadvantaged Youth in Colombia: Evidence from a Randomized Trial

with Adriana Kugler and Costas Meghir (American Economic Journal: Applied Economics, Vol. 3(3), July 2011, pp188-220)

Abstract: This paper evaluates the impact of a randomized training program for disadvantaged youth introduced in Colombia in 2005. This randomized trial offers a unique opportunity to examine the impact of training in a middle income country. We use originally collected data on individuals randomly offered and not offered training. The program raises earnings and employment for women. Women offered training earn 19.6 percent more and have a 0.068 higher probability of paid employment than those not offered training, mainly in formal-sector jobs. Cost-benefit analysis of these results suggests that the program generates much larger net gains than those found in developed countries.
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Risk Sharing in Private Information Models with Asset Accumulation

with Nicola Pavoni (Econometrica, Vol. 79(4), July 2011,  pp1027-68)

Abstract: We study testable implications for the dynamics of consumption and income of models in which first-best allocations are not achieved because of a moral hazard problem with hidden saving. We show that in this environment, agents typically achieve more insurance than that obtained under self-insurance with a single asset. Consumption allocations exhibit “excess smoothness,” as found and defined by Campbell and Deaton (1989). We argue that excess smoothness, in this context, is equivalent to a violation of the intertemporal budget constraint considered in a Bewley economy (with a single asset). We also show parameterizations of our model in which we can obtain a closed-form solution for the efficient insurance contract and where the excess smoothness parameter has a structural interpretation in terms of the severity of the moral hazard problem. We present tests of excess smoothness, applied to U.K. microdata and constructed using techniques proposed by Hansen, Roberds, and Sargent (1991) to test the intertemporal budget constraint. Our theoretical model leads us to interpret them as tests of the market structure faced by economic agents. We also construct a test based on the dynamics of the cross-sectional variances of consumption and income that is, in a precise sense, complementary to that based on Hansen, Roberds, and Sargent (1991) and that allows us to estimate the same structural parameter. The results we report are consistent with the implications of the model and are internally coherent.
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Do House Prices Drive Consumption Growth? The Coincident Cycles of House Prices and Consumption in the UK

with Andrew Leicester and Matthew Wakefield (Journal of the European Economic Association, Vol. 9(3), July 2011, pp399-435)

Abstract: This paper uses a realistic structural lifecycle model of consumption and housing decisions to understand how data might distinguish different mechanisms that explain the correlation between house prices and consumption. The model includes price and earnings shocks estimated from data (the latter including aggregate and idiosyncratic components), and incorporates realistic features of the UK mortgage market. We simulate the model using more than 30 years of realized shocks and under counterfactual scenarios. Our results confirm the intuition of earlier studies: house price shocks should have a larger effect on the consumption of older households and earnings shocks on young households.
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Intertemporal consumption choices, transaction costs and limited participation into financial markets: Reconciling data and theory

with Monica Paiella (Journal of Applied Econometrics, Vol. 26(2), March 2011, pp322-343)

Abstract: This paper builds a unifying framework based on the theory of intertemporal consumption choices that brings together the limited participation-based explanation of the Consumption Capital Asset Pricing Model’s poor empirical performance and the transaction costs-based explanation of incomplete portfolios. Using the implications of the consumption model and observed household consumption and portfolio choices, we identify the preference parameters of interest and a lower bound for the costs rationalizing non-participation in financial markets. Using the US Consumer Expenditure Survey and assuming isoelastic preferences, we estimate the coefficient of relative risk aversion at 1.7 and a cost bound of 0.4% of non-durable consumption. Our estimate of the preference parameter is theoretically plausible and the bound sufficiently small to be likely to be exceeded by the actual total (observable and unobservable) costs of participating in financial markets.
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Consumption and Saving: Models of Intertemporal Allocation and Their Implications for Public Policy

with Guglielmo Weber (Journal of Economic Literature, Vol. 48(3) September 2010, pp693–751)

Abstract: This paper provides a critical survey of the large literature on the life cycle model of consumption, both from an empirical and a theoretical point of view. It discusses several approaches that have been taken in the literature to bring the model to the data, their empirical successes and failures. Finally, the paper reviews a number of changes to the standard life cycle model that could help solve the remaining empirical puzzles.
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Mandated Attendance at Parenting Workshops Improves Womens Healthcare Knowledge But May Widen Health Inequities in Low and Middle Income Countries

with I Forde, T Chandola and M Marmot (Journal of Epidemiology and Community Health, Vol. 64, September 2010, ppA58)

Abstract: Conditional cash transfer schemes (CCTS) are relatively new policies in low and middle income countries which aim  to improve the health and welfare of poor families by investing in their knowledge, skills and resources. Families are offered regular cash as long as they comply with certain conditions. One of these is that mothers/carers attend workshops where parenting and children’s healthcare issues are discussed. We hypothesised that presence of a CCTS in Colombia would be associated with an increase  in women’s healthcare knowledge.
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Mexico in the 1990s: the Main Cross-Sectional Facts

with Chiara Binelli (Review of Economic Dynamics, Vol. 13(1), January 2010, pp238-264)

Abstract: This paper describes the main cross-sectional facts on individual and household earnings, labor supply, income, consumption and wealth in Mexico in the decade of the 1990s. We use two different data sources: the Mexican Employment Survey (ENEU) and the Mexican Income and Expenditure Survey (ENIGH). The contribution of this paper is twofold. First, we integrate the two surveys to provide a complete characterization of the changes in employment, wages, income, consumption and wealth in the 1990s. Second, we highlight some distinctive features that characterize the Mexican economy in this decade. In particular, we focus on the changes in the size of the informal sector and we study the relationship between changes in informality and changes in wage inequality.
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Childrens education and Work in the Presence of a Conditional Cash Transfer Program in Rural Colombia

with Emla Fitzsimons, An Gomez, Marta I. Rodriguez, Costas Meghir and Alice Mesnard (Economic Development and Cultural Change, Vol. 58(2), January 2010, pp181-210)

Abstract: The paper studies the effects of Familias en Acción, a conditional cash transfer program implemented in rural areas in Colombia since 2002, on school enrollment and child labor. Using a difference?in?difference framework, our results show that the program increased school participation of 14–17?year?old children quite substantially, by between 5 and 7 percentage points and had lower effects on the enrollment of younger children, in the region of 1–3 percentage points. The effects on work are largest in the relatively more urbanized parts of rural areas and particularly for younger children, whose participation in domestic work decreased by around 13 percentage points after the program, as compared to a decrease of 10 percentage points for older children in these same areas. The program had no discernible impacts on children’s work in more rural areas. Participation in income?generating work remained largely unaffected by the program. We also find evidence of school and work time not being fully substitutable, suggesting that some, but not all, of the increased time at school may be drawn from children’s leisure time.
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Building Trust? Conditional Cash Transfers Programs and Social Capital

with Luca Pellerano and Sandra Polania-Reyes (Fiscal Studies, Vol. 30(2), June 2009, pp139–177)

Abstract: In this paper, we propose a measure of social capital based on behaviour in a public goods game. We conducted a public goods game within 28 groups in two similar neighbourhoods in Cartagena, Colombia, one of which had been targeted for over two years by a conditional cash transfer programme that has an important social component. The level of cooperation we observe in the ‘treatment’ community is considerably higher than that in the ‘control’ community. The two neighbourhoods, however, although similar in many dimensions, turn out to be significantly different in other observable variables. The result we obtain in terms of cooperation, however, is robust to controls for these observable differences. We also compare our measure of social capital with other more traditional measures that have been used in the literature.
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Oportunidades: Program Effect on Consumption, Low Participation, and Methodological Issues

with Manuela Angelucci (Economic Development and Cultural Change, Vol. 57(3), April 2009, pp479-506)

Abstract: In this paper we estimate the effect of the Mexican conditional cash transfer program, Oportunidades, on consumption, and we explore some issues related to participation to the program and to the estimation of treatment effects. We discuss the comparability of treatment and control areas, provide evidence that the expected transfer may not be sufficiently high to induce many eligible households to participate, and find positive effects on consumption.
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Estimating Euler Equations with Noisy Data: Two Exact GMM Estimators

with S. Alan and M. Browning (Journal of Applied Econometrics, Vol. 24(2), March 2009, pp309-324)

Abstract: In this paper we exploit the specific structure of the Euler equation and develop two alternative GMM estimators that deal explicitly with measurement error. The first estimator assumes that the measurement error is log-normally distributed. The second estimator drops the distributional assumption at the cost of less precision. Our Monte Carlo results suggest that both proposed estimators perform much better than conventional alternatives based on the exact Euler equation or its log-linear approximation, especially with short panels. An empirical application to the PSID yields plausible and precise estimates of the coefficient of relative risk aversion and the discount rate.
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Booms and Busts: Consumption, Expectations and House Prices in the UK

with L. Blow, R. Hamilton and A. Leicester (Economica, Vol. 76(301), February 2009, pp20-50)

Abstract: Over much of the past 25 years, house price and consumption growth have been closely synchronized. Three main hypotheses for this have been proposed: increases in house prices raise household wealth and so their consumption; house price growth reduces credit constraints by increasing the collateral available to homeowners; and house prices and consumption are together influenced by common factors. Using microeconomic data, we find that the relationship between house prices and consumption is stronger for younger than older households, contradicting the wealth channel. We suggest that common causality has been the most important factor linking house prices and consumption.
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Explaining Changes in Female Labor Supply in a Life-Cycle Model

with Hamish Low and Virginia Sánchez-Marcos (American Economic Review, Vol. 98(4), September 2008, pp1517-52)

Abstract: This paper studies the life-cycle labor supply of three cohorts of American women, born in the 1930s, 1940s, and 1950s. We focus on the increase in labor supply of mothers between the 1940s and 1950s cohorts. We construct a lifecycle model of female participation and savings, and calibrate the model to match the behavior of the middle cohort. We investigate which changes in the determinants of labor supply account for the increases in participation early in the life-cycle observed for the youngest cohort. A combination of a reduction in the cost of children alongside a reduction in the wage-gender gap is needed.
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Credit Constraints in the Market for Consumer Durables: Evidence from Micro Data on Car Loans

with Penelopi Goldberg and Ekaterini Kyriazidou (International Economic Review, Vol. 49(2), May 2008, pp401-436)

Abstract: We investigate the significance of borrowing constraints in the market for consumer loans. Using data from the Consumer Expenditure Survey on auto loan contracts we estimate the elasticities of loan demand with respect to interest rate and maturity. We find that, with the exception of high income households, consumers are very responsive to maturity and less responsive to interest rate changes. Both elasticities vary with household income, with the maturity elasticity decreasing and the interest rate elasticity increasing with income. We argue that these results are consistent with the presence of binding credit constraints in the auto loan market.
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The Impact of a Conditional Cash Transfer Programme on Consumption in Colombia

with Alice Mesnard (Fiscal Studies, Vol. 27(4), December 2006, pp421-442)

Abstract: This paper studies the impact of a conditional cash transfer programme in Colombia on the total consumption of very poor households and on its components. Our evaluation methodology involves comparing household expenditures in areas in which the programme was not implemented (control) and those in which it was (treated). We use a quasi-experimental approach, as the Familias en Acción programme was not randomly assigned across localities, for political reasons. We condition on a large range of household- and municipality-level characteristics, and also control for pre-programme differences in the outcomes of interest using a differences-in-differences methodology. We find that the programme has been effective at greatly increasing total consumption and its main component, food consumption, in both rural and urban areas. The programme has also contributed to improvements in the quality of food consumed, in particular of items rich in proteins (milk, meat and eggs) and of cereals. Furthermore, the programme has created redistributive effects in favour of children through expenditure on education and children’s clothing, while it has not significantly affected consumption of adult goods such as alcohol and tobacco or adults’ clothing.
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Quantifying the Effects of the Demographic Transition in Developing Economies

with Sagiri Kitao and Giovanni Violante (The B.E. Journal of Macroeconomics, Vol. 6(1), April 2006)

Abstract: This paper evaluates quantitatively the impact of the observed demographic transition on aggregate variables (factor prices, saving rate, output growth), and on inter-generational welfare in developing economies. It does so by developing a large-scale two-region equilibrium overlapping generations model calibrated to the North (more developed countries) and the South (less developed countries). The paper highlights that the effects of the demographic trends for less developed regions may depend on the degree of international capital mobility and on the extent to which the large Pay-As-You-Go systems in place in the more developed world will be reformed.
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Child health in rural Colombia: determinants and policy interventions

with L.C. Gomez, A. Gomez and M. Vera-Hernandez (Journal of Economics and Human Biology, Vol. 2(3), December 2004, pp411-438)

Abstract: We study the determinants of child anthropometrics on a sample of poor Colombian children living in small municipalities. We focus on the influence of household consumption, and public infrastructure, taking into account the endogeneity of household consumption using two different sets of instruments: household assets and municipality average wage. We find that both household consumption and public infrastructure are important determinants of child health. We have also found that the coverage of the piped water network positively influenced child health if the parents have some education.
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Trade reforms and wage inequality in Colombia

with Pinelopi Goldberg and Nina Pavcnik (Journal of Development Economics, Vol. 74(2), August 2004, pp331-366)

Abstract: We investigate the effects of the drastic tariff reductions of the 1980s and 1990s in Colombia on the wage distribution. We identify three main channels through which the wage distribution was affected: increasing returns to college education, changes in industry wages that hurt sectors with initially lower wages and a higher fraction of unskilled workers, and shifts of the labor force towards the informal sector that typically pays lower wages and offers no benefits. Our results suggest that trade policy played a role in each of the above cases. The increase in the skill premium was primarily driven by skilled-biased technological change; however, our evidence suggests that this change may have been in part motivated by the tariff reductions and the increased foreign competition to which the trade reform exposed domestic producers. With respect to industry wages, we find that wage premiums decreased by more in sectors that experienced larger tariff cuts. Finally, we find some evidence that the increase in the size of the informal sector is related to increased foreign competition—sectors with larger tariff cuts and more trade exposure, as measured by the size of their imports, experience a greater increase in informality, though this effect is concentrated in the years prior to the labor market reform. Nevertheless, increasing returns to education, and changes in industry premiums and informality alone cannot fully explain the increase in wage inequality we observe over this period. This suggests that overall the effect of the trade reforms on the wage distribution may have been small.
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Estimating Euler Equations

with Hamish Low (Review of Economic Dynamics, Vol. 7(2), April 2004, pp406-435)

Abstract: In this paper we consider conditions under which the estimation of a log-linearized Euler equation for consumption yields consistent estimates of the preference parameters. When utility is isoelastic and a sample covering a long time period is available, consistent estimates are obtained from the log-linearized Euler equation when the innovations to the conditional variance of consumption growth are uncorrelated with the instruments typically used in estimation. We perform a Monte Carlo experiment, consisting in solving and simulating a simple life cycle model under uncertainty, and show that in most situations, the estimates obtained from the log-linearized equation are not systematically biased. This is true even when we introduce heteroskedasticity in the process generating income. The only exception is when discount rates are very high (e.g. 47% per year). This problem arises because consumers are nearly always close to the maximum borrowing limit: the estimation bias is unrelated to the linearization and estimates using non-linear GMM are as bad. Across all our situations, estimation using a log-linearized Euler equation does better than nonlinear GMM. Finally, we plot life cycle profiles for the variance of consumption growth, which, except when the discount factor is very high, is remarkably flat. This implies that claims that demographic variables in log-linearized Euler equations capture changes in the variance of consumption growth are unwarranted.
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Wage shocks and consumption variability in Mexico during the 1990s

with Miguel Székely (Journal of Development Economics, Vol. 73(1), February 2004, pp1-25)

Abstract: This paper presents evidence on the relationship between shocks to relative male wages and changes in household consumption in Mexico during the 1990s decade, which is a period characterized by high volatility. Apart from performing analysis of this type for Mexico for the first time, the paper has mainly two contributions. The first is the use of alternative data sources to construct instrumental variables for wages. The second is to examine differences across four consumption categories: nondurable goods, durable goods, education, and health. Our results for nondurable goods consumption reject the hypothesis that Mexican households are able to ensure idiosyncratic risk. For the comparisons across consumption categories, the conclusion is that households in Mexico tend to react to temporary shocks by contracting the consumption of goods that represents longer run investment in human capital, which makes them more vulnerable in the future.
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