Nudging physical activity: evidence from online experiments in six MENA countries

Last registered on November 25, 2025
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Pre-Trial

Trial Information

General Information

Title
Nudging physical activity: evidence from online experiments in six MENA countries
RCT ID
AEARCTR-0017282
Initial registration date
November 20, 2025

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 25, 2025, 7:49 AM EST

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

Locations

Country
United Arab Emirates
Region
MENA
Country
Egypt
Region
MENA
Country
Iraq
Region
MENA
Country
Jordan
Region
MENA
Country
Morocco
Region
MENA
Country
Saudi Arabia
Region
MENA

Primary Investigator

Name
Iman Sen
Affiliation
University of Maryland
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Other Primary Investigator(s)

PI Name
Tasmia Rahman
PI Affiliation
World Bank Group
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PI Name
Sayan Kundu
PI Affiliation
World Bank Group
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PI Name
Mariagiulia Lauro
PI Affiliation
World Bank Group
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Additional Trial Information

Status
In development
Start date
2025-11-24
End date
2026-02-28
Keywords
Behavior, Health
Additional Keywords
social norms, physical activity, norm-sensitive, nudge
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Physical inactivity is a major public health challenge globally, with particularly low rates in the MENA region. This study aims to better understand how social and cultural expectations influence physical activity (PA) among adults in six Middle East and North Africa (MENA) countries (United Arab Emirates, Saudi Arabia, Morocco, Egypt, Iraq, Jordan). Norms and beliefs about need for exercise, gender, family roles, or what others around them are doing can shape people's decisions of whether to engage in PA. At the end of a survey, participants are invited to join a four-week physical activity “check-in” challenge. To learn what types of messages encourage people to participate, we randomly show three different invitations- one highlighting family motivations, another highlighting what people in their community are doing, and a third, neutral version. People who join the challenge will then receive a short message every four days asking about their physical activity over the past 4 days. Those who opt-in to the challenge will be further assigned to one of two groups. Those in the control group will receive a standard message, while those in the treatment group will receive norm-sensitive encouragement messages. This will allows us to examine whether norm-sensitive messages help people stay engaged and report higher levels of activity over time.
External Link(s)

Registration Citation

Citation
Kundu, Sayan et al. 2025. "Nudging physical activity: evidence from online experiments in six MENA countries." AEA RCT Registry. November 25. https://doi.org/10.1257/rct.17282-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2025-12-01
Intervention End Date
2025-12-31

Primary Outcomes

Primary Outcomes (end points)
The main outcome of interest in the recruitment challenge is if the individual signs up to the 4 week physical activity challenge.
The main outcome of interest is the physical activity challenge is reported activity (every 4 days over the 4 weeks). In addition, we will track completion rates over the 4 weeks.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
For the recruitment experiment, individuals will be randomly shown a treatment or a control message at the end of a survey. To learn what types of messages encourage people to participate, we randomly show one of three different invitations- one highlighting family motivations, another highlighting what people in their community are doing, and a third, neutral version.

In the physical activity challenge, respondents are randomly assigned to a treatment or control group (in a 60-40 split). Those in treatment will see six treatment messages over the 4 weeks that were designed to encourage physical activity. The sequence of messages seen by those in treatment will vary. A short survey measuring self-reported physical activity will be collected every 4 days. Respondents will see a new message at the the end of the short survey if assigned to the treatment group. We will treat each weekly message and activity reported after 4 days as an independent experiment.

Experimental Design Details
Not available
Randomization Method
Randomization done by computer.
Randomization Unit
The randomization unit is individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
The recruitment survey is completed after a survey with a sample of 8000 individuals.

The size of the physical activity challenge will vary based on the number who sign up from a related study that has also been registered. The initial survey will be completed with about 8,000 individuals, and we expect a sign up rate of 20% or about 1600 individuals.
Sample size: planned number of observations
The recruitment survey is completed after a survey with a sample of 8000 individuals. In the physical activity challenge, since each weekly message received and activity reported 4 days after is treated as an experiment, the study can have upto 1600 individuals * 7 messages = 11,200 observations. However, the actual number of observations may be lower as respondents may drop out earlier.
Sample size (or number of clusters) by treatment arms
In the recruitment experience, 8000 respondents will be split equally to see the 2 treatment and 1 control message, therefore each arm will be approximately 2,666 individuals.

In the physical activity challenge, we expect approximately 960 individuals assigned to treatment and 640 to control out of the 1600 we expect to sign up. Since we then use each message received as an independent experiment, we may have 1600 individuals * 7 messages = 11,200 observations, which divides into about 6,720 observations in treatment and 4,480 in control. Furthermore, since there are 6 treatment messages, we expect a little over 1000 observations per treatment message.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
HML IRB
IRB Approval Date
2025-11-20
IRB Approval Number
3192
Analysis Plan

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