Misreporting Month Of Birth Implications For Nutrition Research

Height-for-age z-scores (HAZs) and stunting status (HAZ<−2) are widely used to measure child nutrition and population health. However, accurate measurement of age is nontrivial in populations with low levels of literacy and numeracy, limited use of formal birth records, and weak cultural norms surrounding birthdays and calendar use. In this paper we use Demographic and Health Surveys data from 62 countries over the period 1990–2014 to describe two statistical artifacts indicative of misreporting of age. The first artifact consists of lower HAZs for children reported to be born earlier in each calendar year (resulting in implausibly large HAZ gaps between January- and December-born children), which is consistent with some degree of randomness in month of birth reporting. The second artifact consists of lower HAZs for children with a reported age just below a round age (and hence implausibly large HAZ gaps between children with reported ages just below and just above round ages), which is consistent with survey respondents rounding ages down more than they round ages up. Using simulations, we show how these forms of misreporting child age can replicate observed patterns in the data, and that they have small impacts on estimated rates of stunting but important implications for research that relies on birth timing to identify exposure to various risks, particularly seasonal shocks. Moreover, the misreporting we identify differs from conventional age-heaping concerns, implying that the metrics described above could constitute useful markers of measurement error in nutrition surveys. Future research should also investigate ways to reduce these errors.

We are delighted to present to you the first issue of Abstract Digest for this year. This issue has two important LANCET Commission Reports. The EAT–Lancet Commission is the first of a series of initiatives on nutrition, led by The Lancet in 2019, followed by the Commission on the Global Syndemic of obesity, undernutrition, and climate change. Along with these, we have articles from an issue of Public Health Nutrition that focuses on child and adolescent nutrition, and much more.

Health-related incentives to reward effort or commitment are commonplace in many professional contracts throughout the world. Typically absent from small-scale agriculture in poor countries, such incentives may help overcome both health issues for remote rural families and supply issues for firms. Using a randomized control design, we investigate the impact of adding a micronutrient-fortified product in contracts between a Senegalese dairy processing factory and its seminomadic milk suppliers. Findings show significant increases in frequency of delivery but only limited impacts on total milk delivered. These impacts are time sensitive and limited mostly to households where women are more in control of milk contracts.

Estimating future demand for food is a critical aspect of global food security analyses. The process linking dietary changes to wealth is known as the nutrition transition and presents well-identified features that help to predict consumption changes in poor countries. This study proposes to represent the nutrition transition with a nonhomothetic, flexible-in-income, demand system, known as the Modified Implicitly Directly Additive Demand System (MAIDADS). The resulting model is transparent and estimated statistically based on cross-sectional information from FAOSTAT the statistical database of the Food and Agriculture Organization of the United Nations. It captures the main features of the nutrition transition: rise in demand for calories associated with income growth; diversification of diets away from starchy staples; and a large increase in caloric demand for animal-based products, fats, and sweeteners. The estimated model is used to project food demand between 2010 and 2050 based on a set of plausible futures (trend projections and Shared Socioeconomic Pathways scenarios). The main results of these projections are as follows: (1) global food demand will increase by 46 percent, less than half the growth in the previous four decades; (2) this growth will be attributable mainly to lower-middle-income and low-income countries; (3) the structure of global food demand will change over the period, with a 95 percent increase in demand for animal-based calories and a much smaller 18 percent increase in demand for starchy staples; and (4) the analysis of a range of population and income projections reveals important uncertainties depending on the scenario, the projected increases in demand for animal-based and vegetal-based calories range from 78 to 109 percent and from 20 to 42 percent, respectively.

Social protection programs—public or private initiatives that aid the poor and protect the vulnerable against livelihood risks—can effectively be used to assist those trapped, or at the risk of being trapped, in chronic poverty. These programs aim to address chronic poverty through redistribution and protect vulnerable households from falling below the poverty line. Although investments in social protection programs are often motivated by equity concerns, they can also contribute to economic growth by, for example, encouraging savings, creating community assets, and addressing market imperfections. Despite their potential and proliferation, not enough is known about social protection programs in Africa. The 2017–2018 Annual Trends and Outlook Report (ATOR) reduces this knowledge gap by focusing on the potential of such programs on the continent and the corresponding opportunities and challenges. The chapters of the Report highlight the benefits of these programs, not only to their direct recipients but also others in the community through spillover effects. They also underscore the importance of appropriate design and sustainability to fully realize the potential of social protection programs.

While there is a large body of literature on the negative health effects of air pollution, there is much less written about its effects on cognitive performance for the whole population. This paper studies the effects of contemporaneous and cumulative exposure to air pollution on cognitive performance based on a nationally representative survey in China. By merging a longitudinal sample at the individual level with local air-quality data according to the exact dates and counties of interviews, we find that contemporaneous and cumulative exposure to air pollution impedes both verbal and math scores of survey subjects. Interestingly, the negative effect is stronger for men than for women. Specifically, the gender difference is more salient among the old and less educated in both verbal and math tests.

As in many parts of the developing world, the share of high value crops in agricultural gross domestic product (AgGDP) has increased substantially in Nepal. We contribute to the literature on trends in agricultural development in the poorest countries by answering the research question on “Does transition from traditional to high-value agriculture reduce rural poverty in poor developing countries”? We also identified the drivers leading to this transition. The study uses survey data from three rounds of the nationally representative Nepal Living Standard Surveys: NLSS I (1994/1995), NLSS II (2004/2005) and NLSS III (2010/2011). Multi-level model was used to study the determinants of agricultural diversification. To estimate the causal impact of agricultural diversification on welfare measures, propensity score matching and instrumental variable techniques were used. Results indicate that there has been a rightward shift in the distribution of the share (percent) of high-value crops between 1995 and 2004 and between 2004 and 2010, respectively. The area as well as the shared by major cereals (paddy, maize, and wheat) is declining over years. However, it is increasing for high-value crops (potato, vegetables, spices/condiments, and fruits). The percentage increase in share of the high-value crops was higher in or adjacent to urbanized districts between 1995 and 2010. The factors positively associated with the agricultural diversification are female-headed households, caste, mother's education, net-buyer status, urban region, remittance, farm size, kitchen garden, improved seeds, telephone and refrigerator. We found positive impact of agricultural diversification towards high-value crops on rural poverty and monthly per capita consumption expenditure. However, for cereal crops grower, we find the negative impact on poverty and monthly per capita consumption expenditure.

Reducing food loss and waste are important policy objectives prominently featured in the United Nation’s Sustainable Development Goals. To optimally design interventions targeted at reducing losses, it is important to know where losses are concentrated between the farm and fork. This paper measures farmlevel postharvest losses for three main crops—maize, soy, and groundnuts—among 1,200 households in Malawi. Farmers answered a detailed questionnaire designed to learn about losses during harvest and transport, processing, and storage and which measures both total losses and reductions in crop quality. The findings indicate that fewer than half of households report suffering losses conditional on growing each crop. In addition, conditional on losses occurring, the loss averages between 5 and 12 percent of the farmer’s total harvest. Compared to nationally representative data that measure losses using a single survey question, this study documents a far greater percentage of farmers experiencing losses, though the unconditional proportion lost is similar. We find that losses are concentrated in harvest and processing activities for groundnuts and maize; for soy, they are highest during processing. Existing interventions have primarily targeted storage activities; however, these results suggest that targeting other activities may be worthwhile.