The promise of preschool in Africa: a randomized impact evaluation of early childhood development in rural Mozambique

Publication Details

Martinez, S, Naudeau, S and Pereira, V, 2013. The promise of preschool in Africa: a randomized impact evaluation of early childhood development in rural Mozambique, 3ie Impact Evaluation Report 1. New Delhi: International Initiative for Impact Evaluation (3ie)

Link to Source
Sebastian Martinez, Sophie Naudeau, Vitor Pereira
Institutional affiliations
None specified
Grant-holding institution
None specified
Sub-Saharan Africa (includes East and West Africa)
Education, Health Nutrition and Population, Multisector
Pre-Primary and Primary Education, HIV and AIDS, Early Childhood Development Programs
Gender analysis
Pre-Primary and Primary Education, HIV and AIDS, Early Childhood Development Programs
Gender analysis
Equity Focus
Orphans and Vulnerable Children
Evaluation design
Randomised Control Trials (RCT)
3ie Series Report
3ie Funding Window
Open Window Round 1


Save the Children's Early Childhood Development (ECD) project in Mozambique aims to support young children in communities affected by HIV/AIDS by providing community mobilisation and resources for the construction of ECD centres that facilitate children's learning and cognitive development. The ECD programme includes daily 3.25-hour preschool classes with lessons in literacy and math, play time, as well as monthly meetings offered to caregivers of the enrolled children on the subjects of health, nutrition and literacy.
For the purposes of this evaluation, Save the Children randomly selected 30 communities from a sample of 76 to receive access to the ECD programme. The impact analysis rests on panel data collected in early 2008 and early 2010 from a random sample of 2,000 households with preschool-aged children in each of the 76 communities, in addition to surveys of community leaders and first-grade students in each community. The surveys assess child development, including cognitive ability, gross motor skills, fine motor skills, language and communication, socioemotional development and health. Data collected at the household level allow for an analysis of secondary impacts on older siblings and caregivers.
The authors present two models of analysis, intent to treat (ITT) and treatment on the treated (TOT). The ITT model estimates the mean difference in outcomes between treatment and control communities. The model uses treatment status as an instrumental variable for preschool attendance, and uses population weights and robust standard errors clustered at the community level to estimate the regression. The TOT analysis estimates impact on those children who enrolled in preschool using a two-stage least squares model, using an endogenous indicator of preschool attendance and instrumenting for random assignment at the community level. These models are used to assess the impact of the ECD programme on primary school enrollment, child development outcomes, child growth and health and on older siblings and adult caregivers.

Main findings

Under the ITT model, primary school enrollment increased by 5.8 percentage points, or 9 percent, in treatment communities relative to control communities. The TOT analysis estimates the impact for enrolled ECD children to be 15.4 percentage points (24.2 percent), both significant at the 1-percent level. In addition, children who attend preschool were 10.2 percentage points (21.7 percent) more likely to enroll in primary school at the appropriate age.
The data revealed positive and significant TOT impacts of preschool enrollment on indices of cognitive skills (87 percent, p = .05) and precise motor skills (6.7 percent, p = .05). A few indicators of emotional development improved among enrolled children, but the data showed little impact on language and communication skills. Enrolment in the ECD programme did not affect children’s probability of stunting or wasting, or height or weight for age. Health impacts were mixed, with enrolled children reporting a 10-percentage-point increase in the probability of being sick in the past 4 weeks, but also reporting a decrease in skin problems as well as diarrhea.
Notably, older siblings of ECD enrollees aged 10–15 were 4.3 percentage points (p = .1) more likely to be currently enrolled in school and 4.8 percentage points (p = .01) more likely ever to have been enrolled in school. Compared to the controls, caregivers of enrolled children were 26 percent more likely to have worked in the past 30 days (p = .1), possibly due to the 15-hour decrease in child-care duties each week while the child attended school.
These results in the aggregate suggest that, at a cost of US$2.47 per student per month, this intervention was highly effective at improving the lives of preschool children and their families in this context. The authors propose caution when generalizing these results to other contexts. They note that the marginal impact on each additional enrolled child may decrease as enrollment increases, and that the mixed results on language acquisition and health should be considered before scaling up the model.

Additional publications

Media coverage


About this impact evaluation

Early years of life are pivotal in forming the foundations for healthy development and providing children and their societies the opportunity to reach their full potential. Programs to promote early childhood development (ECD) are most critical in Africa, where children face the myriad risks of disease, malnutrition, conflict and low-quality education systems. Governments in Africa urgently need evidence about the effectiveness of ECD programs to help them make informed decisions about the allocation of resources in their struggle to meet basic needs and secure a better future for their citizens.

In response to this imperative for actionable evidence, Save the Children and the World Bank collaborated with local partners to carry out a ground-breaking evaluation of an early childhood development (ECD) program in Gaza Province, Mozambique. This ECD program enrols vulnerable children ages 3-5 – those living amidst high levels of poverty and/or affected by HIV/AIDS – and provides them with a high-quality but low-cost and fiscally scale-able model of pre-school education.

After results of the original evaluation were released, the government asked for a scale up. The World Bank's Strategic Impact Evaluation Fund (SIEF) is now evaluating the scale up, along with testing a nutritional add on for young women. The children, who are now in primary school, were surveyed again in 2014, along with their parents and siblings. 

Read the final report of this project : The Promise of Preschool in Africa : A Randomized Impact Evaluation of Early Childhood Development in Rural Mozambique

World Bank's Evidence to Policy note based on this impact evaluation Is Preschool good for kids?

Read: case studies from this project

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