Young Lives is a longitudinal study that follows the livelihoods of two cohorts of children born between 1990s and 2000s. After tracking 2,750 children for 15 years in Peru, unique evidence about the role of social programs, differences in nutritional and educational trajectories, and skills formation, has been collected.

Young Lives, known in Peru as Niños del Milenio, is a longitudinal study that seeks to understand the causes and consequences of child poverty. Since 2002, it follows the livelihoods of 12,000 children from four developing countries: Ethiopia, India, Peru and Vietnam.

In Peru, Young Lives follows two groups of children selected from 20 districts of the country randomly selected in 2002: the Older Cohort, born in 1994 and followed since the age of eight, and the Younger Cohort, born in 2001 and followed from the first year of age.

In total, approximately 2,750 children have been tracked. These children and their families were visited on five occasions, in 2002, 2006, 2009, 2013 and 2016. The data collected by the study (duly anonymized) are freely available to anyone who wishes to use them for research. Likewise, between 2007 and 2014, a qualitative study was carried out in 4 of the 20 districts in a subgroup of 50 boys and girls from both cohorts.

The Older Cohort was born when the country was emerging from a traumatic period marked by hyperinflation, economic recession, terrorism and political violence. In contrast, the Younger Cohort was born at a more stable period, marked by high-economic growth and higher expenditure in social programs. Because of its longitudinal nature, Young Lives is in a good position to tell the story of these two generations of children born seven years apart, and how they differ from each other.

Throughout the approximately 16 years since the beginning of the study, a large number of studies that use data from Young Lives in Peru on different topics of childhood and adolescence have been published. In “What have we learned from the longitudinal study Young Lives in Peru? Synthesis of Findings”, published by GRADE in Spanish (see a summary in English here), interested readers will find a discussion of the main findings derived from these studies. Here I mention (briefly and selectively) some of these results:

One area in which Young Lives has been relevant is the evaluation of the impact of social programs. For example, JUNTOS is a cash conditional transfer program, and the second largest social program in the country in terms of budget. Because of its timing, only the Younger Cohort benefited from JUNTOS. Using Young Lives data, its (positive) impact on dimensions typically not observed in household surveys has been measured in a number of studies (see, for example, Escobal and Benitez 2012a and 2012b; Andersen et al., 2015). Interestingly, when comparing the members of the Younger Cohort with their younger siblings, it is found that for the latter –whom benefited during the early childhood– the nutritional impact of the program is larger, and only for them a cognitive impact is observed (Sánchez, Meléndez and Behrman, soon to be published at EDCC).

Another area where new knowledge has been generated is the study of the nutritional and growth patterns of children and adolescents in Peru. By comparing the two cohorts we are able to observe there was a reduction in the levels of chronic malnutrition, especially in rural areas, which is consistent with official statistics (Penny, 2018).

But a specific aspect that the longitudinal data allows to observe is that there was also evidence of nutritional recovery; that is, some of those who were chronically malnourished at the first visit of Young Lives later recovered, and these improvements are associated with a recovery in their cognitive performance, although they did not reach the level of those children who were never malnourished (for a review of this literature using Young Lives data, see Benny, Penny and Boyden, 2018).

Thus the evidence shows that investing in early childhood is fundamental, but during childhood and adolescence there is still room for improvement. However, it is not all good news. Young Lives finds that overweight and obesity has increased in recent years and the Younger Cohort children are more likely to be overweight or obese, especially in urban areas. This is expected to lead to a higher prevalence of cardiovascular diseases and diabetes in the future (Penny, 2018).

Young Lives has also generated rich evidence on the learning trajectories of Peruvian children and on the inequities observed in the education system, which do not contribute to attenuate the learning gaps observed since the age of five (Cueto and Felipe, 2018).

Time flies!

Young Lives started as a study about childhood, but the members of the Older Cohort are already young adults. A series of recent studies has generated evidence on the importance of socio-emotional skills and aspirations for long-term outcomes, such as accessing higher education, teenage pregnancy, and engagement in health risk behaviors.

The evidence shows that socio-emotional skills and aspirations are formed throughout the life cycle and are associated with aspects such as the level of household wealth (Dercon and Krishnan, 2009), chronic malnutrition (Sánchez, 2017) and experiences of violence within the household (Bedoya, Espinoza, and Sánchez, 2018).

Overall, Young Lives allows us to document the life trajectories of two groups of Peruvian children born seven years apart, and to understand the opportunities available for them. Please check Niños del Milenio for a comprehensive summary of the main findings.

I would like to conclude by emphasizing the importance of collecting longitudinal data as a means to generate knowledge that is relevant for policy makers interested in designing strategies to improve health and nutrition, learning, and socio-emotional outcomes. Nevertheless, large-scale longitudinal studies are still, and surprisingly, rare in developing countries.

Alan has a DPhil in Economics from the University of Oxford. He also holds a master degree in Economics for Development from Oxford. Currently, he is a Senior Researcher at GRADE and the Principal Investigator of Young Lives Peru.

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