Increasing people's willingness to eat healthier and be more physically active using social norms

Last registered on April 28, 2022


Trial Information

General Information

Increasing people's willingness to eat healthier and be more physically active using social norms
Initial registration date
April 26, 2022

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 28, 2022, 6:12 PM EDT

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



Primary Investigator

B4Development Foundation

Other Primary Investigator(s)

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
As part of a health promotion campaign survey, an experiment will be done to test whether social norm messages can increase respondents' willingness to increase their current level of physical activity and improve their diet. Possible barriers to both types of behaviours will also be explored.
External Link(s)

Registration Citation

Makki, Fadi. 2022. "Increasing people's willingness to eat healthier and be more physically active using social norms." AEA RCT Registry. April 28.
Experimental Details


An experiment embedded within a survey will be conducted whereby social norms related to the physical activity and healthy diet will be tested.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Willingness to increase the current level of physical activity
Willingness to increase current fruits and vegetable consumption
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
There will be three arms - control, treatment arm 1 (nutrition), treatment arm 2 (physical activity). All survey respondents will be randomly assigned to one of the groups.
Experimental Design Details
Randomization Method
Randomization done in office by a computer (STATA)
Randomization Unit
Individual randomization
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
no clusters
Sample size: planned number of observations
1,15 million of patients registered with primary health care centers will receive the text message to participate in the study, the response rate is usually 5-6%, expected number of respondents is app 50 000
Sample size (or number of clusters) by treatment arms
330 000 patients in each of the treatment arms
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials