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Study Overview

Nudging children toward healthier food choices: An experiment combining school and home gardens
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School garden programs have become a popular type of intervention in developing countries, but there is very little evidence to date that such programs lead to improvements in nutrition outcomes. While previous studies demonstrated that school gardens can improve children’s knowledge of and preferences for healthier foods, actual improvement in food behavior may be constrained by low availability of healthy food and the influence of caregivers on children’s diets. This study therefore tests the hypothesis that a school garden programs targeting children if combined with a home garden program targeting their parents—can nudge children aged 8-12 in Nepal toward healthier diets. This is done using a cluster randomized trial in which 30 schools from one district in Nepal are randomly assigned to a control and intervention group. Stratification is used to achieve balance. Using a combination of quantitative and qualitative method the study will provide a deeper understanding of the mechanisms through which school-based interventions can influence children’s food choices and thereby contribute to better nutrition intervention designs globally.
Agriculture and Rural Development
Health, Nutrition, and Population
Additional Keywords:
School garden, home garden, school nutrition, food choices, food behavior, nutrition-sensitive agriculture
Secondary ID Number(s):
Prime Award No. Bill & Melinda Gates Foundation / Department for International Development (DFID): DOPP1110043; Subaward nr. University of South Carolina 18-3578

Principal Investigator(s)

Name of First PI:
Pepijn Schreinemachers
World Vegetable Center
Name of Second PI:

Study Sponsor

UK Government’s Department for International Development and Bill & Melinda Gates Foundation
Study Sponsor Location:
United Kingdom

Research Partner

Name of Partner Institution:
Nepal Agricultural Research Council (NARC), ANSAB, Leibniz Institute of Vegetable and Ornamental Crops (IGZ)
Type of Organization:
Research institute/University

Intervention Overview

The objective of the intervention is to influence the food choices of children 8-12 years old toward healthier diets, including regular consumption of fruit and vegetables. The intervention has two components that are simultaneously implemented in all treatment schools: (a) The school-based component establishes a school garden for the cultivation of nutrient-dense vegetables by the school children under the guidance of teachers and following a standard design. It includes a 23-week curriculum about gardening and nutrition. Vegetable seed and basic equipment and tools are provided by the project. (b) The home-based component targets children’s caregivers (chiefly their mothers) and trains them how to establish a productive home garden and about the importance of nutrition for family health. Caregivers are given small seed packs of the same vegetables as used in the school garden and natural fertilizers. Children are encouraged to help their parents in the home garden while parents help out with the school garden. Regular technical support is provided by a trained field staff.
Theory of Change:
The supply of produce from the school garden can potentially make a direct contribution to increased intake levels among school children, but this is not the main strategy because school gardens are too small to provide a daily meal to hundreds of children. Therefore, the main strategy is for the combination of gardening and education to increase children’s awareness about healthy foods, their knowledge about agriculture and food, and their preferences for healthy eating. These changes are then expected to improve children’s food choices toward healthier diets. Access to healthy food at the household-level is addressed in parallel through a complementary intervention component that trains parents in home gardening and nutrition. Children and parents will be encouraged to do gardening together and for children to apply in the home garden what they have learned at school.
Multiple Treatment Arms Evaluated?

Implementing Agency

Name of Organization:
Nepal Agricultural Research Council (NARC) handles the school garden component; Asia Network for Sustainable Agriculture and Bioresources (ANSAB) handles the home garden component.
Type of Organization:

Program Funder

Name of Organization:
The intervention is funded from the project. Please note that this is an novel intervention evaluated at a pilot stage.
Type of Organization:
Foreign or Multilateral Aid Agency

Intervention Timing

Intervention or Program Started at time of Registration?
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Evaluation Method

Evaluation Method Overview

Primary (or First) Evaluation Method:
Randomized control trial
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Additional Evaluation Method (If Any):
Difference in difference/fixed effects
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Method Details

Details of Evaluation Approach:
The study uses an experimental setup using a cluster RCT design in which villages (and their schools) are randomly assigned to either a control group or a treatment group. The treatment group received both the school garden program and the complementary home garden program while the control group received neither. Power calculations showed that 30 clusters and 30 students per cluster would give sufficient statistical power. An initial list of 65 schools in the study area was stratified based on secondary data on altitude and teacher to student ratio. Stratification was necessary to increase the likelihood of balance as the sample of schools is small. Baseline data were collected from children and parent in May 2018 and endline data will be collected in May 2019. A difference-in-difference estimator will be used to quantify the intervention’s impact.
Outcomes (Endpoints):
Primary - school children: 1. Frequency of vegetable consumption (measured from 24h recall repeated every month) 2. Individual dietary diversity score (measured from 24h recall repeated every month) 3. Snack choices (measured at baseline and endline) Primary - parents: 1. Frequency of vegetable consumption (at baseline and endline) 2. Individual dietary diversity score (at baseline and endline) Secondary - children: 1. Knowledge of agriculture, food and nutrition (at baseline and endline) 2. Stated food preferences (at baseline and endline) Secondary - parents: 1. Knowledge of agriculture, food and nutrition (at baseline and endline) 2. Stated food preferences (at baseline and endline)
Knowledge scores for food and nutrition are constructed from 15 multiple choice questions with 4 choices per question. The score is the proportion of correct answers. Knowledge scores for sustainable agriculture are constructed from 14 photos of common insects. Respondents need to indicate for each insect if it is harmful or beneficial to the vegetable garden. The score is the proportion of correct answers. Food preferences are measured using 10 multiple choice questions with 3 optional snack choices per question. The score will be the proportion of healthier choices. Preference for eating vegetables is measured using 15 photos of uncooked vegetables to which respondents need to indicate their liking on a 5-point likert scale. The score will be expressed as the average liking and scaled from 0-1. Individual dietary diversity score (IDDS) is based on the standard score developed by FAO.
Unit of Analysis:
Individual as well as household
Primary hypothesis: 1. School garden programs can nudge boys and girls aged 8-12 toward healthier food choices if the programs simultaneously (a) increase children’s access to healthy foods within the household and (b) influence the food behavior of their caregivers. Secondary hypotheses: 2a. Increased availability of fruit and vegetables within the household leads to healthier food choices among children and parents. 2b. Improvements in parental knowledge and attitudes about food and nutrition leads to healthier food choices among children and parents.
Unit of Intervention or Assignment:
School garden intervention at the school level; home garden intervention as the household level.
Number of Clusters in Sample:
Number of Individuals in Sample:
900 school children and 900 households
Size of Treatment, Control, or Comparison Subsamples:
450 children and households for the treatment; 450 children and households for the control

Supplementary Files

Analysis Plan:

Outcomes Data

2 surveys among school children (at baseline and endline) 2 surveys among caregivers (at baseline and endline) Food logbooks (24 hour recall) collected monthly from June 2018 to May 2019
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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