NEW UPDATE: Completed trials may now upload and register supplementary documents (e.g. null results reports, populated pre-analysis plans, or post-trial results reports) in the Post Trial section under Reports, Papers, & Other Materials.
The effect of self-chosen goals on exercising
Last registered on February 01, 2018


Trial Information
General Information
The effect of self-chosen goals on exercising
Initial registration date
October 05, 2017
Last updated
February 01, 2018 4:26 AM EST
Primary Investigator
Centre for European Economic Research (ZEW)
Other Primary Investigator(s)
PI Affiliation
University of Gothenburg
Additional Trial Information
Start date
End date
Secondary IDs
We investigate whether self-chosen goals are effective at increasing gym attendance. Members that buy a new contract at the health club we are cooperating with are randomly assigned to one of three groups. Groups 1 and 2 are not asked to state any exercising goals in terms of weekly visits to the gym. The difference between the two groups is that group 1 does not receive any emails, while the group 2 receives very general reminders about the opportunity to exercise at the club every month. The third group is asked to state an explicit exercising goal in terms of weekly attendance when they sign up at the gym. In addition, this group receives the same, very general reminder emails that are sent to group 2. However, in addition to the general content used in the emails to group 2, these emails also contain the individual exercising goals as stated when buying the contract. We will collect detailed attendance data during the intervention period, as well as during (at least) three subsequent months to investigate long run effects.
External Link(s)
Registration Citation
Habla, Wolfgang and Paul Muller. 2018. "The effect of self-chosen goals on exercising." AEA RCT Registry. February 01. https://doi.org/10.1257/rct.2492-2.0.
Former Citation
Habla, Wolfgang, Wolfgang Habla and Paul Muller. 2018. "The effect of self-chosen goals on exercising." AEA RCT Registry. February 01. http://www.socialscienceregistry.org/trials/2492/history/25396.
Experimental Details
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
- Gym attendance (daily)
- Type of attendance (free training or group exercise classes)
- Booking of classes and cancellation of class bookings
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The sample contains all individuals that bought a 12-months gym membership between the beginning of October 2017 and the beginning of December 2017 at a large health club with several locations. We observe whether these individuals had a previous membership in the preceding six months. Both new and existing members will be included in the analysis.
Starting in November or December, individuals in treatment groups 2 and 3 will receive reminders. In treatment 2, these will be very general reminders about the opportunity to attend the gym (similar to Habla and Muller, 2017, but in monthly instead of weekly intervals). In treatment 3, the same reminders will be sent, but including the stated goals. Emails will be dispatched once a month. Participants can unsubscribe at any time if they do not wish to receive any further messages. The reminders will be sent over the course of at least six months. Group 1 will not receive any email reminders during this period, except for a newsletter from the health club that is sent approximately once every six weeks (also to groups 2 and 3).
Experimental Design Details
Randomization Method
When buying the membership at the reception, each individual will be asked to complete a form with a few short questions regarding gym attendance. Some of the forms will contain an additional question about exercising goals. The forms are prepared in random order, such that one-third of the participants will answer the question on exercising goals.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
700 individuals
Sample size: planned number of observations
700 individuals
Sample size (or number of clusters) by treatment arms
1/3 of the treatment size for each treatment arm
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)