Why aren't all early childhood interventions most effective at the same age? Should we be checking that our randomizations are balanced according to genes that influence behavior? Should we be gathering biological outcomes, in addition to economic ones, even when the intervention does not involve biology?
Early childhood interventions - usually working through either health or education – can have very long-lasting effects, some of which are even transmitted to the next generation. Two weekends ago, the Chicago Initiative for Economic Development and Early Childhood (CEDEC) held a conference to survey what is known in this area and provide a forum for sharing findings from recent projects.
In today's post, I highlight a few bits of the presentations that taught me something I didn't know, gave me a reference I wanted to hold on to, or put old findings in a new perspective.
The conference was interdisciplinary, featuring economists, psychologists, child development specialists, and studies from a variety of countries (even a study of non-human primate behavior). Presentations included methodological innovations, analyses of causal effects of interventions, and novel statistical associations that survive inclusion of enough controls that one starts to wonder whether the links are indeed causal.
A basic insight driving the conference, verbalized by Jim Heckman and Martha Nussbaum (among others), is that if we are concerned with poverty or inequality, we may equally be concerned with poverty or inequality of opportunities and capabilities (in the direction of Amartya Sen's work). To the extent that those are constrained by the environment a child experiences early in life, it essential that we consider interventions that are useful at that age. These interventions may have great complementarities with subsequent investments.
Some highlights that stood out to me:
Tools you can use
Lia Fernald presented a toolkit for cognitive assessments in early childhood - a wealth of information if you are interested in collecting data - linked here.
The role of biology: mechanisms for economic effects...
Biologically measurable processes play an important role in linking early childhood shocks to adult outcomes, even when outcomes are economic. Biomarkers for inflammation are one such group of measures, including C-reactive protein. Elevated levels of this and related biomarkers are known risk factors for disease, and in recent work, Andrea Danese and colleagues find elevated inflammation indicators for children who experienced maltreatment in early childhood.
(See the 2007 paper, linked here.)
Greg Duncan and colleagues have been working for some time now on US data from the Panel Study of Income Dynamics, showing that parents' income in the first several years of a child's life are much more predictive of that child's adult outcomes than are parents' incomes in later years. (See, for example, Duncan, Ziol-Guest, and Kalil 2010.) The remarkable connection to Danese's work is that this same identification strategy shows that a child whose parents had higher incomes in the first five years of the child's life also have lower rates of inflammation-linked conditions, such as arthritis and hypertension, in adulthood.
...and variation in effects based on biological markers.
The Fragile Families study at Princeton is now looking into whether behavioral responses to shocks differ across individuals, according to genetic markers. (An example of this kind of research is this 2011 PNAS paper on genes that appear to influence psychological reactions to shocks.) Much of this work is still ongoing, but we can look forward to publications from this group in the coming year or two. Lots of related work is already linked on their website.
Lasting impacts and heterogeneity
Paul Gertler discussed his work with Christel Vermeersch and an array of co-authors carrying out the latest follow-up of the very well-known Jamaica study by Sally Grantham-McGregor, Susan Walker, and others. Early childhood nutrition and stimulation among stunted children in Jamaica had very positive effects. The nutrition intervention yielded improved physiological growth, though those effects seemed to fade with time. The stimulation intervention, on the other hand, (basically, encouraging sophisticated play involving both children and their mothers or caregivers) had lasting effects on IQ in the teen years, and it seems, wages in adulthood.
Costas Meghir presented some very preliminary results from work that he, Sally Grantham-McGregor, Orazio Attanasio, Emla Fitzsimmons, and Marta Rubio Codina have undertaken in Colombia, building on the lessons from the project in Jamaica, but this time on a larger scale: randomizing treatment arms among 1,400 participants (compared to a few hundred in Jamaica).
Preliminary results in Colombia suggest that the stimulation intervention is having a large impact; perhaps the largest impact is appearing for children who were 18-24 months old at baseline, rather than 12-17 months old. (This might because these are children for whom more complex types of play are actually feasible.)
Jere Behrman put things in perspective: in the well-known INCAP study in four villages in Guatemala, where nutritional supplementation seems to have lasting effects, stunting rates in the population were close to 50%. In Guatemala, nutrition is a really serious issue. In Jamaica, the stunting rate is closer to 4%, so while Walker, Grantham-McGregor, and co-authors identified undernourished children in Jamaica for their study, nutrition simply isn't as prominent a concern in Jamaica in general as it is in Guatemala. Colombia, according to the numbers he showed, is somewhere in between these two cases. Bottom line: similar interventions have different effects, depending on the conditions in the area at the time.
Owen Ozier is an economist in the Development Research Group, currently studying health, education, and economic decisions in Kenya.