Creating Exercise Habits Using Incentives: The Tradeoff between Flexibility and Routinization
Last registered on October 22, 2018

Pre-Trial

Trial Information
General Information
Title
Creating Exercise Habits Using Incentives: The Tradeoff between Flexibility and Routinization
RCT ID
AEARCTR-0003471
Initial registration date
October 19, 2018
Last updated
October 22, 2018 1:06 AM EDT
Location(s)
Region
Primary Investigator
Affiliation
Other Primary Investigator(s)
PI Affiliation
PI Affiliation
PI Affiliation
PI Affiliation
Additional Trial Information
Status
Completed
Start date
2015-03-03
End date
2016-01-26
Secondary IDs
ClinicalTrials.gov Identifier NCT02346799
Abstract
The purpose of this study is to determine whether healthy habits can be formed more effectively when people are rewarded for repeated engagement in a given healthy behavior at a specific, routinized time each day rather than at any time.
External Link(s)
Registration Citation
Citation
Beshears, John et al. 2018. "Creating Exercise Habits Using Incentives: The Tradeoff between Flexibility and Routinization." AEA RCT Registry. October 22. https://www.socialscienceregistry.org/trials/3471/history/36047
Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2015-03-03
Intervention End Date
2015-03-31
Primary Outcomes
Primary Outcomes (end points)
gym visits during the four-week intervention period and gym visits during the four weeks following the intervention period
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Participants will be randomly assigned in pairs to three conditions:
1) control: receive daily reminder emails before the two-hour workout window selected at the beginning of the study
2) flexible incentives: in addition to daily reminder emails, receive $3 or $7 (randomly assigned at the beginning of the study) for each gym visit that is completed during the four-week intervention period (up to one per day)
3) routine incentives: in addition to daily reminder emails, receive $3 or $7 (randomly assigned at the beginning of the study) for each gym visit that is completed during the four-week intervention period _and_ that is initiated during the two-hour workout window selected at the beginning of the study
[note that a planned fourth experimental condition was dropped because study enrollment was lower than targeted]
Experimental Design Details
Randomization Method
randomization done by a computer
Randomization Unit
pairs of participants (participants registered for the study in pairs)
Was the treatment clustered?
Yes
Experiment Characteristics
Sample size: planned number of clusters
1254 pairs of participants
Sample size: planned number of observations
2508 participants
Sample size (or number of clusters) by treatment arms
66 pairs assigned to control, 597 pairs assigned to flexible incentives (300 pairs with $3 incentives, 297 pairs with $7 incentives), 591 pairs assigned to routine incentives (297 pairs with $3 incentives, 294 pairs with $7 incentives)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Study has received IRB approval. Details not available.
IRB Approval Date
Details not available
IRB Approval Number
Details not available
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
Yes
Intervention Completion Date
March 31, 2015, 12:00 AM +00:00
Is data collection complete?
Yes
Data Collection Completion Date
January 26, 2016, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication
Data Publication
Is public data available?
No
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers