Breaking habits

Last registered on January 28, 2019
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Pre-Trial

Trial Information

General Information

Title
Breaking habits
RCT ID
AEARCTR-0003822
Initial registration date
January 25, 2019

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
January 28, 2019, 2:50 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

Country
Netherlands
Region
City of Tilburg

Primary Investigator

Name
Ben Vollaard
Affiliation
Tilburg University
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Daan Soest
PI Affiliation
Tilburg University
Contact Investigator

Additional Trial Information

Status
Completed
Start date
2014-09-01
End date
2015-12-01
Keywords
Environment & Energy
Additional Keywords
habit formation, intrinsic motivation, deterrence, crackdown
JEL code(s)
D03, Q53
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
Soest, Daan and Ben Vollaard. 2019. "Breaking habits." AEA RCT Registry. January 28. https://doi.org/10.1257/rct.3822-1.0
Former Citation
Soest, Daan and Ben Vollaard. 2019. "Breaking habits." AEA RCT Registry. January 28. https://www.socialscienceregistry.org/trials/3822/history/40730
Sponsors & Partners

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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 (Hidden)
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)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
Yes
Intervention Completion Date
August 07, 2015, 12:00 +00:00
Data Collection Complete
Yes
Data Collection Completion Date
December 01, 2015, 12:00 +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, Papers & Other Materials

Relevant Paper(s)

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.
URL
https://surfdrive.surf.nl/files/index.php/s/5aN3W3raOrdtI4k

Reports & Other Materials