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Study Overview

Impact of school gardens on children’s knowledge and food intake at school and at home: Evidence from Benin
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To address food and nutrition issues among school kids, the Government of Benin in partnership with the World Food Program (WFP) has initiated a school canteen intervention. The intervention focuses essentially on providing cereals, fortified oil, legumes and iodized salt to children in selected primary schools. In collaboration with WFP, the World Vegetable Centre (WorldVeg) is implementing the project “Production and promotion of nutrient rich foodstuffs to address the double burden of malnutrition” hereafter called Nutrifood. Within the framework of Nutrifood, WorldVeg introduced in pilot WFP-supported schools an approach that involves establishing school gardens to supply school canteens with fresh vegetables. The approach includes a community nutrition component where school kids and some community members are trained on good cooking practices. Additionally, some community members are also encouraged to adopt home gardens to produce vegetables that will further supply the school canteens. To generate some rigorous evidence of the Nutrifood approach, WorldVeg initiated a quasi-experimental Impact Evaluation study to measure the impact of the project children’s Knowledge, Attitudes and Practices (KAP) on food, good agriculture practices and intake of vegetables. Our identification strategy relies on a quasi-experimental approach and more specifically on a Difference-in-Difference (DiD) methodology. The study involves 30 schools and up to 1324 school kids, 30 teachers, and 62 community members. 

Registration Citation:
Agriculture and Rural Development
Health, Nutrition, and Population
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Principal Investigator(s)

Name of First PI:
Rosaine N. Yegbemey
World Vegetable Center
Name of Second PI:
Pepijn Schreinemachers
World Vegetable Center

Study Sponsor

World Vegetable Center
Study Sponsor Location:

Research Partner

Name of Partner Institution:
World Food Program (Benin)
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Intervention Overview


The intervention that we will evaluate is a school garden program linked to a school feeding program. Here, school gardens will be combined with home gardens managed by community members and nutrition-related activities (i.e., culinary demonstrations of veggies, WASH awareness and nutrition knowledge through nutrition games) which are some tools that Nutrifood pilots to break the cycle of malnutrition affecting many schoolchildren in Benin. The intervention includes two main components:

  • The training component: This is a group training (at school level) to teach practical aspects related to common and nutritious vegetable identification, designing nutritious, locally and culturally acceptable recipes and consumption, vegetable nursery making, key good agricultural practices in safe leafy and fruit vegetable production, compost preparation and key vegetables seeds regeneration. Additionally, healthy food systems aspects, healthy eating behavior and nutritious diets are integrated in the teaching materials. 
  • The production component:  To establish a school garden, Nutrifood supply schools with vegetable seeds and small production equipment (hoes, watering cans, etc.). The project works with teachers, schoolchildren (students of primary school levels 4 and 5) and community members volunteers. In addition to those groups of actors, WFP delegated some mandated NGOs members to supervise activities and help to mobilize the communities and convince them of the necessity of their collaboration. Vegetables produced and harvested on the school gardens supply the school canteen. In addition, vegetables produced by up to five volunteer community members on their home gardens also supply the school canteen. Community members benefit from seed kits distribution to engage in home garden production with the commitment to supply the school canteen.
Theory of Change:

The simplified ToC of the intervention suggests that implementing a school garden program can improve children’s perception of a healthy diet. As the school gardens will be set-up in schools with canteen and the products from the gardens will supply the school kitchen, we expect to see improvements in children´s knowlege about good agricultural practices (including nutritional aspects of food) and food intake at school. Furthermore, on the basis that school children are good ambassadors of the training and can restitute the new knowledge anywhere and help to change behavior about vegetable consumption, it is expected that food intake at home will also increase

Multiple Treatment Arms Evaluated?

Implementing Agency

Name of Organization:
World Vegetable Center
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Program Funder

Name of Organization:
GCRF-BBSRC (The Global Challenges Research Fund, Biotechnology and Biological Science Research Council), UK
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Intervention Timing

Intervention or Program Started at time of Registration?
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Evaluation Method

Evaluation Method Overview

Primary (or First) Evaluation Method:
Difference in difference/fixed effects
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Method Details

Details of Evaluation Approach:

Our identification strategy relies on a quasi-experimental approach and more specifically on a Difference-in-Difference (DiD) methodology. The study involves tree groups: i) Nutrifood schools: This is our treatment group, including WFP schools that enjoy the Nutrifood project; ii) Non-Nutrifood schools: This is a comparison group composed of WFP schools that have a school garden but do not enjoy the Nutrifood project; and iii) No garden schools: This is a pure comparison group composed of WFP schools that have no school garden and also do not enjoy the Nutrifood project. The 10 schools involved in the Nutrifood project are the treatment group (i.e., Nutrifood schools). As these schools were not selected randomly, we first relied on WFP experts to shortlists up to 15 similar schools (based on the size of the school, geographic location, land available for school garden and the existence of a source of water) in each the non-Nutrifood and the no garden school groups. Then, a school level paired-wise matching was done, using the psmatch2 command in Stata that relies on a one-to-one nearest-neighbor matching approach. Variables included in the matching were the school kids/lecture ratio, the numbers of school kids enrolled in each level 4 and 5, the school success rate at the 2021 primary school ending certificate, the availability of a source of water and the land acreage available for home garden. In practice, two separate matches were done. The first between the 10 NUTRIFOOD schools and the 15 shortlisted non-NUTRIFOOD schools; and the second between the 10 NUTRIFOOD schools and the 15 shortlisted no garden schools. A total of 10 matched schools were selected after each matching. 

Outcomes (Endpoints):

Nine (09) outcome variables divided into divided into four categories are considered in the evaluation: 

Food intake: Children’s intake of vegetables and fruits at school & Children’s intake of vegetables and fruits in their household

Knowledge on good agricultural practices in safe leafy and fruit vegetable production: Participation in school garden, Vegetable Identification score, Knowledge score on vegetable consumption advantages, Knowledge score on different stages of vegetable production, Knowledge score of the main agricultural practices for leafy vegetable and fruit production

Nutrition knowledge: Knowledge scores on nutrition and health (Food categories, including vitamins, etc.)

WASH awareness: Knowledge scores on good hygiene and sanitation practices


Unit of Analysis:
School kids

Primary research questions

  1. Does the school garden program improve children’s knowledge about food and agriculture practices including nutritional aspects?
  2. Does the school garden program improve children’s intake of vegetables and fruits at school?
  3. Does the school garden program improve children’s intake of vegetables and fruits in their household?

Secondary research questions

  1. What are the challenges related to the implementation of the garden program?
  2. What are the conditions that need to be in place to ensure the sustainability of the school garden program?


Unit of Intervention or Assignment:
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Size of Treatment, Control, or Comparison Subsamples:
(10 schools, up to 44 kids per school in each Nutrifood schools, Non-Nutrifood, and no garden schools

Supplementary Files

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Outcomes Data

We will use primary data collected from a baseline and endline surveys on school kids.
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Treatment Assignment Data

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Data Analysis

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Study Materials

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Registration Category

Registration Category:
Prospective, Category 1: Data for measuring impacts have not been collected

Completion Overview

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Preliminary Report:
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Data Availability

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Other Materials

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Study Stopped