Nudging Children to Make Healthier Food Choices and the Information Environment: Evidence from Indonesia

Last registered on September 27, 2020


Trial Information

General Information

Nudging Children to Make Healthier Food Choices and the Information Environment: Evidence from Indonesia
Initial registration date
November 14, 2019

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
November 15, 2019, 10:03 AM EST

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

Last updated
September 27, 2020, 10:56 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator

Erasmus University Rotterdam

Other Primary Investigator(s)

PI Affiliation
PI Affiliation
PI Affiliation

Additional Trial Information

Start date
End date
Secondary IDs
The study examines the effectiveness of nutrition-related nudges among primary school students using a lab-in-the-field food choice experiment in urban Indonesia. The rapid economic development of Indonesia is accompanied with important changes in lifestyles and diets. The shift of people’s dietary consumption towards processed foods dense in calories, fat, and sugar is accompanied by reduced intake of fruits and vegetables. Especially for children, this nutrition transition may have long-term consequences of an increased risk of non-communicable diseases.

The aim of this study is to evaluate the effect of simple nudges to encourage children’s healthier food choices, and to examine how such effects vary depending on the information environment. Specifically, we will study how nudges work with and without prior exposure to educational messages about healthy eating. Provision of information about healthy nutrition is a cornerstone of many interventions to improve people’s diets. However, by themselves educational messages tend to have weak effects and so we aim to investigate their interactive effect with nudging treatments. The study aims to inform policymakers and future studies on efficient approaches to healthy eating interventions targeted at children.
External Link(s)

Registration Citation

Agustina, Rina et al. 2020. "Nudging Children to Make Healthier Food Choices and the Information Environment: Evidence from Indonesia." AEA RCT Registry. September 27.
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Experimental Details


In a simple, one-shot snack choice experiment between a healthy (banana) and unhealthy, processed food (chocolate covered snack cake), we test three nudging treatments (T1, T2, T3). We compare choices with one control arm without any nudges (Base). This study will inform potential scale-ups of such nudges.

In addition, we study above treatments within two randomized group treatments (4 children) (Block 1: short nutrition video, Block 2: no video).
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
A binary indicator based on the observed choice between a fresh banana and a chocolate-covered snack cake with marshmallow (banana=1, zero otherwise).
Primary Outcomes (explanation)
Children are participating in a one-off, snack choice experiment. They make a choice between a healthy and unhealthy, processed snack.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Study Population
The study uses a randomized control design at the child level based among 7-10 year old children (grades 2-5) in 20 public primary schools in Central Jakarta.

The schools were selected using simple random sampling from a database of 279 primary schools in Jakarta provided by The Ministry of Education and Culture. We further checked the schools’ eligibility to participate in the study by verifying whether they are not currently enrolled in any other nutrition programs, and have a homogeneous student population.

Parental Survey
Before the experiment we ask parents to sign an informed consent form and to fill a survey in which we will collect contextual information on the child’s socio-economic background, anthropometrics (height and weight) etc..

Eligible Sample
All target group children for whom prior parental consent is obtained are eligible to participate in the study. Children with food allergies are excluded.

Snack Choice (Primary Outcome Variable)
During the experiment the children are participating in a snack choice experiment (similar to List and Samek, 2015). They make a choice between a healthy and unhealthy snack. Each child sees a table with a plain tray on which a chocolate covered snack cake and a banana are placed.

We collaborate with teachers. At least one is present during the data collection. The teacher’s presence is meant to provide comfort and safety of children to participate in the study. However the teacher does not observe a child while he/she is choosing a snack.

Treatments (Details Hidden)
Before the snack choice some groups of children receive nutrition information:
-Randomized information provision by video

During the snack choice some children are further exposed to individual treatments:
-Three one time nudge treatment arms during the snack choice.
Experimental Design Details
Experimental Conditions and Expected Effects
a)Individual Treatments
The experiment has the following conditions at the child level (the hypothesized direction of the effect on the likelihood of taking up a healthy snack compared to the base condition is given in parentheses):

-Base – no nudge. The child simply sees a table with a plain tray on which a chocolate covered snack cake and a banana are placed.

-T1 (“Sticker”) – “emoji” stickers are placed next to foods when child makes the choice - a sticker with a green smiley for banana, a sticker with a red “unhappy” face for chocolate covered snack cake. (+)

-T2 (“Banana Peer”) – the child first sees his/her peer (we define «peer» as the same age and same sex individual, and we use “actors” from the child’s class) leaving the room with a banana, then makes the food choice. (+)

-T3 (“Cake Peer”) – the child first sees his/her peer leaving the room with a chocolate covered snack cake, then makes the food choice. (-)

b)Blocks (Group Level Information Provision)
In addition to the individual treatments, we vary information provision in two blocks at a group level (up to 4 kids):

In block 1 prior to the snack choice we show a three-minute educational video. Our video is based on the “MyPlate” materials adapted to the local context and contains “emojis” – a green “smiley face” next to “healthy snacks” (fruits and vegetables), and a red “unhappy face” next to “unhealthy snacks” (chocolate bars, candies and cookies). The script for voice over was adapted from the script used by List and Samek (2015), and it was adjusted in line with Indonesian nutrition guidelines. The message in the video is conveyed by two (a boy and a girl) child actors (8-9 years old) each of whom can be perceived as a “peer” by the participating children.

In block 2, children see no video and participate in the experiment without prior exposure to any educational information about healthy eating from our side.

We expect choices to be healthier on average after seeing the educational video compared to no video.

Interaction of Blocks and Individual Treatments
We further hypothesize that the positive effects of T1 and T2 on healthy snack picking will be magnified after seeing the educational video. The interaction between the video and T3 is ambiguous.

Sequence of the Experiment
The experimental sequence is the following:
- randomization of treatment sequence, participation order and blocks (see details below)
- a group of children watches short educational video about healthy eating (block 1 only)
- children one-by-one are invited to the experiment room
- a pair of snacks (banana and chocolate snack cake) is placed on the tray in the room
- an actor is located behind the door to the room with either a healthy or unhealthy snack in his/her hand visible to the subject (T2 or T3)
- enumerator opens the door, the actor is leaving the room (T2 or T3)
- enumerator asks the child to pick one snack he/she wants to have at the moment. (The enumerator turns away to allow for a private choice)
- enumerator records the child’s choice of snack after child leaves
- kids do post-experimental quiz

We will provide average treatment effects for the two block samples separately. We will use a linear regression model to estimate differences in means – both unconditional as well as adjusted for pre-determined child and family co-variates (if balanced by treatment). We will also check for robustness using probit or logit models. Missing or non-response outcomes are checked for systematic link to treatment.

Heterogeneity of treatments will be studied by testing for the equality of coefficients associated with the respective treatments between blocks. We will also test for the overall difference in means between block 1 and block 2.
We will also provide an exploratory heterogeneity analysis by gender and age.

Standard Errors
We will cluster the standard errors at the class level. We will also provide standard errors clustered at the group (information blocks) level in a robustness check.

Further Analysis
In a short survey after the snack choice, we will ask children what they think their friends picked, as well as what they think their teachers or parents would have picked for them. We will also ask them questions why they picked the banana/chocolate cake. We will use this information in an exploratory fashion (correlating variables with treatment and with their choice) to better understand observed choices, expectations and treatment effects. We also ask children to name their friends to correlate choices within networks. We will also correlated choices with data collected from parents.
Randomization Method
In class - public lottery: Kids pick number to determine sequence of participating in the food choice.
We randomize sequence of block 1 (video) or block 2 (no video) per class.
We randomize sequence of individual treatments for each block.
Randomization Unit
Individual level randomization of experimental conditions: base, T1, T2, T3.
Group level randomization to video (block 1) or no video (block 2).
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
~400 groups (50% block 1, 50% block 2).
Sample size: planned number of observations
1600 children
Sample size (or number of clusters) by treatment arms
Base: 400 (50% in block 1, 50% in block 2)
T1: 400 (50% in block 1, 50% in block 2)
T2: 400 (50% in block 1, 50% in block 2)
T3: 400 (50% in block 1, 50% in block 2)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Sample size was determined based on power calculation for the test of differences in proportions. Our power calculations were focusing on the individual treatments to be able to test individual treatment effects treating the two block samples separately (that is in the separate samples with and without information provision). We did not power the experiment to be able to test differences in treatment effects between the blocks. More specifically, we assumed that in the control condition 57% of children will pick the chocolate cake. We further assumed that the nudge will reduce the proportion to 42% picking the chocolate cake (a reduction of a little more than 25%). In STATA 13.0 the command [sampsi 0.57 0.42, power(0.8) alpha(0.05)] provided a sample size of 187 per experimental arm within each block. We rounded up to 200 observations. The target total sample size for four treatment arms and two information blocks is therefore 1600 (4 conditions * 200 kids * 2 blocks).

Institutional Review Boards (IRBs)

IRB Name
Ethics Committee, Institute of International Social Studies
IRB Approval Date
IRB Approval Number
Ethics 2018‐07


Post Trial Information

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