Skip to main content
Usable Knowledge

The Costs of Poverty

One third of 3- and 4-year-olds in the developing world are not meeting basic milestones. What can be done?
The Costs of Poverty

More than a third of children living in low- and middle-income countries fail to meet basic cognitive and socio-emotional milestones, putting them at risk for lifelong deficits in mental and physical health, educational achievement, and financial stability, according to a new study by psychologist Dana McCoy of the Harvard Graduate School of Education

The study, appearing in the journal PLOS Medicine, is the first to directly estimate the extent of global challenges to children’s healthy development. McCoy and colleagues at the Harvard T. H. Chan School of Public Health, where the research was conducted, used data collected between 2005 and 2015 from caregivers of about 100,000 three- and four-year-old children, in 35 low- and middle-income countries around the world. They extrapolate from that data to estimate that 80.8 million of the roughly 240 million preschool-aged children in the world’s 132 low- and middle-income countries are not meeting age-appropriate benchmarks. McCoy and colleagues estimate that an additional 17 percent of children in these countries are physically stunted. 

What It Means

“Early childhood is a period of rapid growth and development, when children are acquiring a wide range of skills related to physical movement, communication, thinking and planning, and self control,” McCoy says. “Our study focused only on a narrow set of these skills, including children's ability to follow simple directions, work independently, maintain attention, get along with others, and inhibit aggressive behaviors like hitting and kicking.”

Previous research has shown that delays and deficits in these essential skills can lead to negative outcomes in school — and over the course of a lifetime, she says.

What Could Help

What are the interventions that can reverse these setbacks? Previous research has suggested that “reducing adversity and promoting learning in the first 1,000 days of life is particularly critical, as this is a period when children's brains are most sensitive to environmental input,” McCoy says. A number of programs are working to do that — to reduce exposure to violence, malnutrition, and poverty, or to enhance children's access to responsive, enriching interactions with caring adults, which play a critical role in a child's healthy development. Some of these interventions, like an early childhood home visiting program in Jamaica, have shown particular promise.

That program began in the 1970s with the aim of improving mothers’ knowledge about how to play and interact with their young children, McCoy says. “As adults, individuals whose mothers participated in this program when they were young showed higher IQ, better math and reading abilities, reduced levels of depression, and less violent behavior than their peers in the control group,” she says. They even realized greater earning power as adults.

Why It’s Important

But McCoy’s study shows that barriers to healthy development are widespread and stubborn, with consequences for our shared future in a global society. More research is needed to understand how to scale these effective early interventions and to adapt them to specific countries and cultures, she says.

The Sustainable Development Goals recently adopted by the United Nations signal “the importance of early childhood development as a priority in the global development agenda, including for high-income countries like the U.S.,” McCoy adds. “To optimize our long-term, collective potential as a global community, we must focus first on investing in our youngest citizens.”

Additional Resources


Get Usable Knowledge — Delivered
Our free monthly newsletter sends you tips, tools, and ideas from research and practice leaders at the Harvard Graduate School of Education.  Sign up now.

Usable Knowledge

Connecting education research to practice — with timely insights for educators, families, and communities

Related Articles