Sports Buddies: How peer feedback shapes exercise commitment

Last registered on September 12, 2025
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Pre-Trial

Trial Information

General Information

Title
Sports Buddies: How peer feedback shapes exercise commitment
RCT ID
AEARCTR-0016689
Initial registration date
September 09, 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
September 12, 2025, 10:24 AM EDT

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

Locations

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Primary Investigator

Name
Hana Dadic
Affiliation
University of Bern
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Other Primary Investigator(s)

PI Name
Michèle Kaeser
PI Affiliation
University of Bern
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PI Name
Danièle Hafner
PI Affiliation
University of Bern
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Additional Trial Information

Status
In development
Start date
2025-09-10
End date
2026-12-31
Keywords
Behavior, Health
Additional Keywords
Field experiment, goals, feedback, peers, social image concerns
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This project examines how the source of motivational feedback – whether selected by a peer or a computer – affects individuals' exercise levels. We plan to conduct a framed field experiment in collaboration with a Swiss university sports facility. Participants will sign up individually, set their weekly exercise goal (in number of sports facility visits), and will then be randomly matched with another participant with the same exercise goal, who will be their “sports buddy” for the remainder of the study (Gershon et al., 2024). After each week, all participants will receive descriptive feedback about their own and their buddy’s goal achievement. The control group receives no additional motivational feedback, while two treatment groups receive motivational messages from a predefined set of quotes (Moreno-Jaimes & Meza, 2020). In one treatment, the quotes are randomly selected by a computer, while in the other, they are chosen by the participant’s buddy. By systematically varying the source of feedback, we assess whether peer-driven motivation is better at supporting goal achievement than computer-based motivation. Our study offers relevant insights for practice, as it shows how digital fitness apps, workplace wellness programs, and health interventions can leverage social accountability as a cost-effective behavioral tool to improve adherence to exercise goals.
External Link(s)

Registration Citation

Citation
Dadic, Hana, Danièle Hafner and Michèle Kaeser. 2025. "Sports Buddies: How peer feedback shapes exercise commitment." AEA RCT Registry. September 12. https://doi.org/10.1257/rct.16689-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We will implement two experimental conditions and one control condition:
• Control condition: Participants receive descriptive information on their own and their buddy’s goal achievement.
• Automatic Feedback Treatment: Like the control condition, but participants also receive motivational feedback randomly selected by a computer.
• Peer Feedback Treatment: Like the control condition, but participants also receive motivational feedback selected by their buddy.
Intervention Start Date
2025-10-19
Intervention End Date
2026-06-30

Primary Outcomes

Primary Outcomes (end points)
Number of sports facility visits per week (max. 1 per day), goal attainment
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Social image concerns, Other in the Self (IOS) 11 Scale, Motivation to attend Unisport activities
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We will conduct a framed field experiment in collaboration with a Swiss university sports facility to investigate how different sources of motivational feedback – selected by a peer or a computer – affect individuals' exercise levels. Participants’ visits to the sports facilities will be measured through check-in-tools implemented for this study. Each sports visit will count towards a lottery where participants can win vouchers after the study is completed. Only participants who complete all three surveys will be eligible for the draw of the prize winners.

The experiment will proceed as follows:
• Before study:
- Participants will be recruited through various online and offline marketing channels.
- Interested participants can sign up for the study during the recruiting phase via an online registration form (will include study information, social image concerns, motivation to attend Unisport activities, sports activity questions, demographics, informed consent).
- After recruiting is closed, buddy dyads will be randomly formed based on the same self-set goals, and then randomly assigned to one of the treatments. Afterwards, participants will be informed about their assigned buddy and asked to complete a buddy survey (will include IOS scale and question on buddy familiarity).

• During study:
- Pre-intervention: All participants will receive a weekly WhatsApp message including descriptive information on their own and their buddy’s goal achievement
- Intervention: In addition to the message with descriptive information, participants will receive the following second WhatsApp message:
- Control condition: Filler information
- Automatic Feedback Treatment: Filler information + feedback randomly selected by a computer.
- Peer Feedback Treatment: Filler information + feedback randomly selected by their buddy.
- After the final WhatsApp message of the intervention, participants will be asked to complete the closing survey, which will assess social image concerns, the Other in the Self (IOS) 11 Scale, motivation to attend Unisport activities along with a range of control variables, such as failure aversion, academic workload during the study, and types of activities most frequently attended.
- Post-intervention (4 weeks): Participants do not receive any WhatsApp messages anymore, but each sports facility visit still counts towards the prize draw.
Experimental Design Details
Not available
Randomization Method
Computer
Randomization Unit
Buddy dyad
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
Our minimum number of clusters is 105 buddy dyads. The final number of clusters will be determined by recruiting as many participants as possible during the recruitment period.
Sample size: planned number of observations
Our minimum sample size for recruiting is at least 210 participants (i.e., 105 buddy dyads). The sample size will be determined by recruiting as many participants as possible during the recruitment period. We will exclude subjects: - Who cannot be matched with a buddy at the start of the study. - Who miss confirming the first WhatsApp message before the start of the study. - (For Peer Feedback only): Whose buddy fails to select a feedback quote more than twice.
Sample size (or number of clusters) by treatment arms
For each of the three treatments: Minimum 70 participants (i.e., 35 buddy dyads).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
The Ethics Committee of the Faculty of Business, Economics and Social Sciences of the University of Bern
IRB Approval Date
2025-09-09
IRB Approval Number
2025-01
Analysis Plan

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