Long-Run Returns to Early Child Education in Africa: A Randomized Impact Evaluation of Preschools in Mozambique

Last registered on April 10, 2026
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Pre-Trial

Trial Information

General Information

Title
Long-Run Returns to Early Child Education in Africa: A Randomized Impact Evaluation of Preschools in Mozambique
RCT ID
AEARCTR-0018319
Initial registration date
April 09, 2026

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
April 10, 2026, 5:13 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

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Primary Investigator

Name
Vitor Pereira
Affiliation
Universidade Federal do Rio de Janeiro
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Other Primary Investigator(s)

PI Name
Pedro Carneiro
PI Affiliation
University College London
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PI Name
Sebastian Martinez
PI Affiliation
International Iniciative for Impact Evaluation
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Additional Trial Information

Status
In development
Start date
2008-01-01
End date
2028-12-31
Keywords
Education, Gender, Labor, Welfare
Additional Keywords
Early childhood development
JEL code(s)
I21, I25, J13, J24, O15, C93
Secondary IDs
Comité Institucional de Bioética para a saúde de gaza IRB00002657
Prior work
This trial is based on or builds upon one or more prior RCTs.
Abstract
This study evaluates the long-term impacts of a community-based preschool program randomized across 76 rural communities in Gaza
Province, Mozambique in 2008. Save the Children assigned 30 communities to receive preschools serving children aged 3–5, and 46
communities served as controls. A baseline cohort of approximately 2,000 children was surveyed in 2008, with follow-up surveys in 2010 and 2014. Short- and medium-term evaluations showed significant gains in cognitive development, school readiness, socio-emotional skills, and primary school enrollment. By 2026, cohort members will be 21–23 years old. This long- run follow-up — the first experimental long-run evaluation of preschool in a Sub-Saharan African setting — will assess impacts on educational attainment, labor market participation and earnings, health, risky behaviors, fertility and family formation, geographic mobility, and intergenerational transmission of human capital to participants' own children. Randomization was conducted at the community level, stratified into 37 blocks by population size. The intervention and control groups each include communities across three districts. The study will track the full baseline cohort of ~1,907 individuals, using CAPI surveys and qualitative methods to assess causal long-run effects.
External Link(s)

Registration Citation

Citation
Carneiro, Pedro, Sebastian Martinez and Vitor Pereira. 2026. "Long-Run Returns to Early Child Education in Africa: A Randomized Impact Evaluation of Preschools in Mozambique." AEA RCT Registry. April 10. https://doi.org/10.1257/rct.18319-1.0
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Experimental Details

Interventions

Intervention(s)
The intervention was a community-based preschool program implemented by Save the Children in Gaza Province, Mozambique, between 2008 and 2010. Thirty communities were randomly selected to receive preschools (escolinhas) serving children aged 3–5. Program components included: (1) construction of preschool infrastructure by community members; (2) selection and training of community volunteer educators (animadoras), who received one week of pre-service training and monthly mentoring, plus a stipend of approximately $10/month; (3) a play-based curriculum targeting five developmental domains — language and communication, cognitive development, socio-emotional skills, motor skills, and basic numeracy and literacy — delivered in the local language (Changana) with introduction to Portuguese; (4) regular parenting meetings covering child development, hygiene, nutrition, and school readiness; and (5) a management committee appointed by each community. Children attended 3–5 hours per day, five days per week. No food supplementation was
provided. The program explicitly aimed to support transition to primary school, including joint welcome days with local primary schools.
Intervention Start Date
2008-01-01
Intervention End Date
2012-12-31

Primary Outcomes

Primary Outcomes (end points)
1- Educational attainment: years of completed schoolin; primary school completion; secondary school completion/enrollment; university
completion/enrollment 2- Employment and income: employment status (currently working); labor market income (log of wage); profits from business or farm activities; age at first job; formal vs. informal employment
3- Health: self-reported health status; HIV and tuberculosis status; self-reported weight and height; malaria in last year; hospitalization in last year
Primary Outcomes (explanation)
Educational attainment will be measured by self-report and cross-validated with school administrative records (class registers, grade transition reports, national exam scores for grades 5/6, 7, 10, 12) collected from schools in the 76 evaluation communities. Employment status is a binary indicator of current employment. Labor income will be measured in local currency and onverted to log wages for analysis.
Health outcomes will be self-reported with reference periods (e.g., last year). HIV status will be self-reported.

Secondary Outcomes

Secondary Outcomes (end points)
1- Health-seeking behavior: physical activity; frequency of health check- ups; medicines taken in last year; last HIV test
2- Risky behavior: involvement in violence or crime; substance use (tobacco, alcohol, other drugs); unprotected sex; number of sexual
partners; gambling; reckless driving 2- Impulsive behavior 3- Cognitive ability: cognitive test scores; executive function; vocabulary 4- Socio-emotional and psychosocial skills 6- Fertility and family formation: age at first birth; age at first marriage; number of children; household formation 7- Migration and mobility: internal migration (province-level); international migration (primarily South Africa); reason for migration
8- Intergenerational transmission: children's birthweight, APGAR scores, preschool enrollment, and early developmental indicators
9- School administrative registries from chilren in the study area
Secondary Outcomes (explanation)
Risky behavior and substance use will be measured through self-report using validated items. Cognitive outcomes will use standardized test
instruments (e.g., TVIP vocabulary). Socio-emotional outcomes will use standardized and validated instruments. Fertility and migration outcomes are self-reported. Intergenerational outcomes will be collected for children of cohort members. Composite indices for outcome domains will be constructed using inverse covariance weighting or non-linear factor analysis as appropriate. School administrative registries will be obtained by scanning registries from around 70 schools in the study area.

Experimental Design

Experimental Design
This is a cluster-randomized controlled trial with two arms: treatment (preschool program) and control (no preschool program). Randomization was conducted at the community level across 76 communities in three districts in Gaza Province: Manjacaze, Xai-Xai, and Bilene (laterthe districts of Limpopo and Choene were created by splitting Xai Xai district). Communities were stratified into 37 blocks based on population size; one community per block was randomly assigned to treatment, yielding 30 treatment and 46 control communities. The evaluation cohort consists of 2000 children aged 3–5 at baseline in 2008. This long-run follow-up will re-contact the full baseline cohort in 2026, when participants are aged 21–23.
Experimental Design Details
Not available
Randomization Method
Communities were stratified into 37 blocks based on population size drawn from the 2007 National Census. Within each block, one community was randomly assigned to treatment by computer-generated random assignment. Block randomization was used to improve balance between treatment and control groups and increase statistical power. In areas with fewer than 18 communities, blocks consisted of pairs; in areas with 18 or more communities, blocks consisted of triplets. Seven additional replacement blocks were designated but not used, as all 30 initially selected treatment communities accepted the program.
Randomization Unit
Community (village)
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
76 communities
Sample size: planned number of observations
2000 individuals from the original 2008 baseline cohort, plus parents, siblings, and children of cohort members residing in the same household at follow-up. Additionally, school administrative records will be collected for all students in schools in the 5 study districts, expanding the sample for education outcomes analysis.
Sample size (or number of clusters) by treatment arms
Treatment arm: 30 communities,
Control arm: 46 communities

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Minimum detectable effect sizes for 80% of power Log of wage: 21% change (0.2 sd) Currently employed: 9 pp (0.22 sd) Primary school complete: 8 percentage points (0.15 sd) High school complete: 9 pp (0.22 sd) College completion: 3 pp (0.15 sd)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan