The Persistent Effects of Stunting

In this new research, we propose to return to the 130 treated and control communities that constituted the experimental sample of Pantawid (Chaudhury, Friedman, and Onishi 2013) to assess the height of children in both treated and control areas and from non-beneficiary households, as well as cognitive, educational and health related outcomes. The question asked by this study is: what are the medium run effects of early life nutritional deficits proxied by stunting? Stunting is associated with early life cognitive impairment, but does this association persist approximately ten years later?

To answer this question, we will compare the cohort of non-beneficiary children in treated villages who faced the general equilibrium effects documented in Filmer et al. (2023) in utero or in the first 1000 days of life to the same cohort in unaffected control communities. Comparing non-beneficiary cohorts in treated communities to the same cohort in similarly-poor households in communities that were randomized out of the program leverages the exogenous variation generated by randomized treatment assignment. This comparison will allow us to answer whether early-life impacts on stunting are sustained, or, conversely, whether catch-up growth at later ages can reverse the heretofore presumed persistence of stunting by age 3 into later life. Recent work with the Young Lives data suggests the possibility of some catch-up growth but not among the most stunted children (Georgiadis, 2017; Singh, 2017). If we find that stunting by age three does not predict assessed height by ages nine to twelve well, we will examine the possible mechanisms that led the reversal of early life patterns. To do so, we will rely on a reconstructed history of household resources, work patterns, and other activities. Recent evidence from Jamaica (Gertler et al., 2014) and Colombia (Baez and Camacho, 2011; Duque, Rosales-Rueda, and Sanchez, 2018) shows that cognitive deficits associated with stunting can be overcome through stimulation activities, suggesting that this relationship may not be as rigid as originally believed. Conversely, of course, one could see improvements in stunting but not in cognition if there is a differential elasticity of height or cognition to nutrition in the later years of childhood. This component of the study would thus test the hypothesis that early child nutritional deficits have serious long-term developmental impacts. This study should convincingly identify the impact of early life stunting on both later childhood height-for-age and cognitive outcomes.

2023-07-01

2024-03-31

Height-for-age z scores, school attendance, cognitive and socioemotional skills

The proposed study will follow up with approximately 650 children from treated and control villages, who lived in households that were not eligible for the transfer (if in a treated village) or would not have been eligible for the transfer (if in a control village). These children were between 6 and 36 months old at the time of the 2011 survey and will be between 9 and 12 years of age at the time of the proposed follow up. As described above, the assignment to treatment or control villages was randomized and community characteristics across treatment and control exhibited a high degree of balance. Household eligibility for the transfer was determined by a 2008 listing database on household wealth. Therefore, this sample remains experimental and will enable us to rigorously identify the medium-run effects of early life stunting.

We estimate effects by comparing ineligible households (non-poor but with young children) in treated villages to those in control villages. In 2012, after the first-round impact evaluation, the control villages were included in the Pantawid program. Thus, the identification of impact between treatment and control groups concerns the three-year experimental period when the cohort of children born 2008 – 2010 were differentially exposed to the program.

The data we intend to use are from the 2011 survey, a planned 2023-24 follow up, administrative data on school enrollment and test scores, and the Philippine’s household expenditure survey, the FIES. The 2011 survey was conducted by the World Bank, including members of the team proposing the current study. All best practices in data collection were followed, and the survey yielded high quality data, including on anthropometry.

Several categories of outcomes are of potential relevance to the proposed study. The first set, of course, are anthropometric outcomes, which will determine whether early life changes in stunting persist. In addition, evidence suggests that early life investments in, or indeed insults to, health and nutrition lead to sustained effects on cognitive ability. Therefore, we will measure cognitive outcomes as well as possibly relevant socioemotional and other non-cognitive outcomes. Cognitive and socioemotional tests appropriate for this age group include Raven’s Progressive Matrices to measure non-verbal cognitive ability, reading comprehension and vocabulary tests as well as specially designed games to assess behavioral dimensions such as persistence and curiosity. We will also seek to measure recent disease incidence to understand whether the CCT or early-life stunting affect the predisposition to chronic disease.

Not available

Medium-run (14 year follow up) effects of randomization done in office by a computer in 2009

Village

Yes

130

650 non-beneficiary children

65 treated villages, 65 control villages; approximately 350 non-beneficiary children in treated villages and 300 in control villages