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A randomized experiment to investigate the effects of increasing sophistication on stated demand for commitment and time inconsistency in physical activity.
Last registered on October 18, 2019

Pre-Trial

Trial Information
General Information
Title
A randomized experiment to investigate the effects of increasing sophistication on stated demand for commitment and time inconsistency in physical activity.
RCT ID
AEARCTR-0004857
Initial registration date
October 18, 2019
Last updated
October 18, 2019 10:40 AM EDT
Location(s)

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Primary Investigator
Affiliation
Erasmus University Rotterdam
Other Primary Investigator(s)
PI Affiliation
Erasmus University Rotterdam
PI Affiliation
Erasmus University Rotterdam
Additional Trial Information
Status
In development
Start date
2019-10-21
End date
2020-04-30
Secondary IDs
Abstract
Commitment contracts have been shown to be effective to overcome time inconsistent health behavior, including physical activity. However, the take-up of these contracts is usually low. According to several behavioral economic theories, including the quasi-hyperbolic model and dual-self models, the demand for commitment should be increasing in the individual's sophistication, or awareness of their time inconsistency problems. We posit that an intervention to increase sophistication can boost the demand for commitment. We also test the relation between the level of sophistication and the level of time inconsistent preferences (the extent to which an individual's ex-ante ideal level of physical activity exceeds the actual physical activity they carry out). The dual-self model predicts that the level of time inconsistent preferences is decreasing in sophistication, while the quasi-hyperbolic model suggests that this level is independent of sophistication. We carry out these tests in a large multi-wave general population survey, where we measure the time inconsistency, sophistication and stated demand for commitment in physical activity of respondents. We allocate a subset of this population to a treatment to increase their sophistication, and measure the treatment effect on time inconsistency, sophistication and demand for commitment.
External Link(s)
Registration Citation
Citation
O Ceallaigh, Diarmaid, Kirsten I.M. Rohde and Hans van Kippersluis. 2019. "A randomized experiment to investigate the effects of increasing sophistication on stated demand for commitment and time inconsistency in physical activity.." AEA RCT Registry. October 18. https://doi.org/10.1257/rct.4857-1.0.
Sponsors & Partners

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Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2019-10-21
Intervention End Date
2020-04-30
Primary Outcomes
Primary Outcomes (end points)
Physical activity sophistication levels, time inconsistent behavior, time inconsistent preferences and demand for commitment.
Primary Outcomes (explanation)
Note: This is a three-wave longitudinal survey with each survey completed by respondents approximately 2 weeks apart.
Physical activity sophistication levels will be measured by comparing ex-post hours of physical activity actually carried out (as reported by respondents in wave 2(3) of the survey) to ex-ante predictions made by respondents of hours of physical activity for those two weeks (as made in wave 1(2) of the survey).
Time inconsistent behavior will be measured using the same comparison as above, as ex-ante predictions also represent ex-ante plans for physical activity.
Time inconsistent preferences will be measured by comparing ex-post hours of physical activity actually carried out (as reported in wave 2(3) of the survey) to the respondent's ex-ante ideal hours of physical activity for those two weeks (as reported in wave 1(2) of the survey).
Stated demand for commitment will be measured in each of waves 1-3 using hypothetical questions eliciting demand for commitment devices where repayment of a deposit or payment of a reward is contingent on meeting physical activity targets.
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We randomly assign respondents to a control group or to one of two different treatment groups, which receive a sophistication intervention. Further details are provided in the Hidden Experimental Design which will be visible after the completion of the study.
Experimental Design Details
Not available
Randomization Method
Randomization carried out automatically in Qualtrics online survey software.
Randomization Unit
Individual
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
N/A
Sample size: planned number of observations
Invitations to take part in this survey will be sent out to approximately 65,000 members of the Lifelines general population cohort study in the Netherlands. We estimate that approximately 15,000 respondents will complete all three waves of the survey.
Sample size (or number of clusters) by treatment arms
5,000 respondents per group (equal allocation of the expected number of respondents of 15,000 between control and two treatment groups).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Medisch Ethische Toetsingscommissie METC UMC Groningen
IRB Approval Date
2019-09-03
IRB Approval Number
METc 2019/464