Impact of Differently Framed Public Commitment Interventions on Healthy Food Choices - Evidence from Type 2 Diabetes Patients in China

Last registered on October 22, 2025
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Pre-Trial

Trial Information

General Information

Title
Impact of Differently Framed Public Commitment Interventions on Healthy Food Choices - Evidence from Type 2 Diabetes Patients in China
RCT ID
AEARCTR-0016454
Initial registration date
October 15, 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
October 22, 2025, 1:11 PM EDT

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

Last updated
October 22, 2025, 2:52 PM EDT

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

Locations

Country
China
Region
Country
Netherlands
Region

Primary Investigator

Name
Robert Lensink
Affiliation
University of Groningen
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Robert Lensink
PI Affiliation
PI Name
Annika Mueller
PI Affiliation
PI Name
Yu Chen
PI Affiliation

Additional Trial Information

Status
Completed
Start date
2025-03-01
End date
2025-07-31
Keywords
Behavior, Electoral, Health
Additional Keywords
JEL code(s)
Secondary IDs
KT2023-149-01(Ethical Approval number)
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Chronic diseases such as Type 2 Diabetes (T2D) pose major health and economic challenges in developing countries, where healthcare resources are constrained. Effective disease management often requires sustained lifestyle changes, particularly in dietary behavior. This study evaluates the effectiveness of public commitment interventions framed by cultural values in improving dietary self-management among T2D patients in China. We conducted a randomized controlled trial with 480 participants recruited from community health centers in Zhanjiang, in collaboration with Guangdong Medical University and its Affiliated Hospital. Participants were randomly assigned to one of three groups: a control group receiving standard information on carbohydrate intake, a treatment group co-signing a collectivism-based contract emphasizing social responsibility, and another treatment group co-signing an individualism-based contract emphasizing personal health benefits. All participants used a WeChat-integrated mini-program to log daily food intake and monitor carbohydrate consumption. Outcomes include daily carbohydrate adherence, clinical health indicators (HbA1c, blood pressure, weight), logging compliance, psychological responses, cultural orientation, and quality of life. By testing culturally tailored commitment devices, this study contributes to understanding how collectivist versus individualist framing influences long-term health behaviors. The findings will inform scalable, low-cost interventions for chronic disease management and provide evidence for culturally sensitive public health communication in China.
External Link(s)

Registration Citation

Citation
Chen, Yu et al. 2025. "Impact of Differently Framed Public Commitment Interventions on Healthy Food Choices - Evidence from Type 2 Diabetes Patients in China ." AEA RCT Registry. October 22. https://doi.org/10.1257/rct.16454-1.1
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention (Hidden)
Intervention Start Date
2025-03-01
Intervention End Date
2025-06-01

Primary Outcomes

Primary Outcomes (end points)
1. Clinical health assessments – blood pressure, weight, blood glucose, and HbA1c, measured at baseline and endline
2. Compliance with food choice logging – consistency of recording meals in the mini-program (measured in days per week logged)
3. Individual carbs intake
4. Self-reported questionnaire outcomes
Primary Outcomes (explanation)
Regarding the self-reported questionaires outcomes, include the outcomes as follows:
Quality of life (EQ-5D dimensions: mobility, self-care, activities, pain/discomfort, psychological well-being)
Family support in dietary change
Carbohydrate literacy and nutrition knowledge
Psychological responses to dietary adherence (e.g., guilt/shame proneness)
Dietary habits and self-management behaviors
WeChat usage and engagement with the intervention materials
Recall and compliance with the signed contract/information sheet

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Participants were stratified and randomly assigned to three groups. In brief, in the control group, participants first received an information sheet mentioning their daily carbohydrate intake, and then utilized the mini-program integrated with WeChat, the most prevalent social software in China, for self-monitoring their daily carbohydrate intake.
In treatment group one, besides utilizing the mini-program, participants were required to co-sign a contract using collectivistic framing with an assistant. In treatment group two, alongside the use of the mini-program, participants were asked to co-sign a contract using individualistic framing with an assistant.
The contract driven by collectivism underscored the social benefits and responsibilities associated with diabetes prevention for patients, whereas the contract motivated by individualism emphasized the individual benefits of diabetes prevention.
Experimental Design Details
Randomization Method
randomization done in office by a computer.
Randomization Unit
individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
480 individuals
Sample size: planned number of observations
480
Sample size (or number of clusters) by treatment arms
160 participants for one treatment arm.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Affiliated Hospital of Guangdong Medical University The Clinical Research Ethics Committee
IRB Approval Date
2024-07-22
IRB Approval Number
KT2023-149-01
Analysis Plan

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Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials