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Breaking habits
Last registered on January 28, 2019

Pre-Trial

Trial Information
General Information
Title
Breaking habits
RCT ID
AEARCTR-0003822
Initial registration date
January 25, 2019
Last updated
January 28, 2019 2:50 AM EST
Location(s)
Primary Investigator
Affiliation
Tilburg University
Other Primary Investigator(s)
PI Affiliation
Tilburg University
Additional Trial Information
Status
Completed
Start date
2014-09-01
End date
2015-12-01
Secondary IDs
Abstract
We provide rare evidence for how a temporary incentive can kick-start an improved habit. We conducted a natural field experiment involving 70,000 households in an urban area. We study the extent to which they separate their waste, a behavior that is prone to habit formation. The incentive consisted of a letter informing households that disposal of non-separated waste is illegal and punishable by a fine, followed by an intensive and highly salient crackdown of four weeks. The crackdown had a large and instantaneous effect on household behavior. Most of the effect was still apparent up to seven months later. The stable, higher rate of separating waste is likely to have been sustained by a new, improved habit: crowding out of intrinsic motivation by the transactional motive to avoid punishment is found to be only transitory. In contrast to the threat of punishment, two behavioral interventions, one conveying the injunctive norm, another one the descriptive norm, are not found to have any effect.
External Link(s)
Registration Citation
Citation
van Soest, Daan and Ben Vollaard. 2019. "Breaking habits." AEA RCT Registry. January 28. https://doi.org/10.1257/rct.3822-1.0.
Former Citation
van Soest, Daan and Ben Vollaard. 2019. "Breaking habits." AEA RCT Registry. January 28. https://www.socialscienceregistry.org/trials/3822/history/40730.
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Experimental Details
Interventions
Intervention(s)
The treatment consists of informing all households by way of a letter from the municipality of Tilburg that not separating waste is illegal and punishable by a fine of €90, followed by a one-month, intensive and highly salient enforcement campaign.
Intervention Start Date
2014-12-01
Intervention End Date
2015-08-07
Primary Outcomes
Primary Outcomes (end points)
weight of residual waste collected by Department of Sanitation (tons)
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
a. Waste collected: organic waste, plastic and paper
b. Survey response on question ‘Separating waste is a societal duty’
Secondary Outcomes (explanation)
a. Additional types of waste
b. Measure of intrinsic motivation
Experimental Design
Experimental Design
We randomize the timing that a garbage collection route is to receive the treatment over a period of eight months. Randomization involved 60 of the 65 routes; the first five were pre-selected by the municipality because of implementation considerations. This phase-in design came down to randomizing the order in which the twelve remaining collection routes for a specific day of the week were to be treated (e.g. the twelve Monday routes; one Monday route was left out of randomization).

To increase the chance that on average similar routes were treated at different times, we used stratified random ordering of the timing of the treatment based on two variables: the share of residual waste in total waste pre-treatment (September-November 2014), and the percentage of terraced houses on a route in 2014. Both variables are indicators of the (lack of) potential for separation of waste. Once the ordering of the twelve routes for each day of the week was determined, we combined them into groups of five for a complete week of treatment in the Tilburg area.
Experimental Design Details
Randomization Method
Randomization done in office by a computer
Randomization Unit
Garbage collection route.
Was the treatment clustered?
Yes
Experiment Characteristics
Sample size: planned number of clusters
65
Sample size: planned number of observations
65 routes * 16 months * 4 weeks = 4,160
Sample size (or number of clusters) by treatment arms
Due to phase-in design, eventually all 65 routes will be treated.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
IRB Approval Date
IRB Approval Number
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
Yes
Intervention Completion Date
August 07, 2015, 12:00 AM +00:00
Is data collection complete?
Yes
Data Collection Completion Date
December 01, 2015, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
65 routes
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
4,185
Final Sample Size (or Number of Clusters) by Treatment Arms
Due to phase-in design, all routes were eventually treated.
Data Publication
Data Publication
Is public data available?
No

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Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers
Abstract
We provide rare evidence for how a temporary incentive can kick-start an improved habit. We conducted a natural field experiment involving 70,000 households in an urban area. We study the extent to which they separate their waste, a behavior that is prone to habit formation. The incentive consisted of a letter informing households that disposal of non-separated waste is illegal and punishable by a fine, followed by an intensive and highly salient crackdown of four weeks. The crackdown had a large and instantaneous effect on household behavior. Most of the effect was still apparent up to seven months later. The stable, higher rate of separating waste is likely to have been sustained by a new, improved habit: crowding out of intrinsic motivation by the transactional motive to avoid punishment is found to be only transitory. In contrast to the threat of punishment, two behavioral interventions, one conveying the injunctive norm, another one the descriptive norm, are not found to have any effect.
Citation
Van Soest, Daan, and Ben Vollaard, 2019, Breaking habits, unpublished manuscript, Tilburg University.