The Impact of Group Commitment Contracts on Smoking Cessation and Weight Loss
Key facts
- Who runs it
- National Bureau of Economic Research, Inc.
- Where
- Evanston, United StatesSee the site
- Trial code
- Status
- Suspended
- People taking part
- 3,600 people, planned
- Started
- 18 Dec 2023
- Ended
- 19 Jun 2025
- Type of study
- Interventional, 7 groupsOne group gets no study treatment, for comparison.
- Treatments tested
- Group Commitment Contract
- Individual Monetary Rewards
- Individual Commitment Contract
- Information
- Record updated
- 16 April 2024
- Why it stopped
- This study was suspended due to low take-up in the group commitment contracts arm (\~6%), revealing inadequate statistical power to justify moving forward. There were no safety concerns.
Who can take part
- Age
- 18 years and older
- Sex
- Women and men
- Healthy volunteers
- Can take part
The registry criteria, word for word
Show all 9 criteriaShow less
Who can take part
- Aged 18 years or older
- Has smartphone with capability to reach internet daily and download app
- Able and willing to visit Quest location or take an at-home verification test
- Willing to furnish a payment method for commitment contract stakes; If completing a smoking cessation contract:
- Daily smoker; If completing a weight loss contract:
- Has access to a functioning scale
- Interest in losing weight at a pace of 2 lb or fewer per week, with a target BMI at or above 18.5
Who cannot take part
- Any terminal illness
- Pregnancy
Where in United States
- Northwestern University, Global Poverty Research LabEvanston, United States
About the trial
What the trial wants to find out
We will conduct a randomized controlled trial to evaluate the effectiveness of group commitment contracts for smoking cessation and weight loss.
The 7 groups in the trial
- ControlNo study treatment, for comparison
Subjects are not offered a group commitment contract, individual commitment contract, or individual monetary rewards. Subjects do not receive additional information treatments.
- Group Commitment Contract + InformationTreatment being tested
Subjects are offered a group commitment contract for smoking cessation or weight loss and receive additional information treatments.
Treatment: Group Commitment Contract and Information
- Individual Monetary Rewards + InformationTreatment being tested
Subjects are offered individual monetary rewards for smoking cessation or weight loss and receive additional information treatments.
Treatment: Individual Monetary Rewards and Information
- Individual Commitment Contract + InformationTreatment being tested
Subjects are offered an individual commitment contract for smoking cessation or weight loss and receive additional information treatments.
Treatment: Individual Commitment Contract and Information
- Group Commitment ContractTreatment being tested
Subjects are offered a group commitment contract for smoking cessation or weight loss and receive no additional information treatments.
- Individual Monetary RewardsTreatment being tested
Subjects are offered individual monetary rewards for smoking cessation or weight loss and receive no additional information treatments.
- Individual Commitment ContractTreatment being tested
Subjects are offered an individual commitment contract for smoking cessation or weight loss and receive no additional information treatments.
Data and sources
- Registry record
- Listed on ClinicalTrials.gov.
- Record updated
- 16 April 2024