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Nudging to reduce littering in waste disposal areas – A field experiment in Austria’s community houses
Last registered on June 30, 2020

Pre-Trial

Trial Information
General Information
Title
Nudging to reduce littering in waste disposal areas – A field experiment in Austria’s community houses
RCT ID
AEARCTR-0006108
Initial registration date
June 30, 2020
Last updated
June 30, 2020 12:11 PM EDT
Location(s)

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Primary Investigator
Affiliation
Institute for Advanced Studies
Other Primary Investigator(s)
PI Affiliation
Institute for Advanced Studies
PI Affiliation
Institute for Advanced Studies
Additional Trial Information
Status
In development
Start date
2020-06-30
End date
2020-09-11
Secondary IDs
Abstract
This field experiment tests an intervention to reduce littering in waste disposal areas in community houses in Vienna/Austria. Community houses differ in size from about 20 apartments in some houses to over 2000 apartments in other houses. The inhabitants take away their garbage bags in shared waste disposal areas. Waste disposal areas in community houses are often littered. This problem causes monetary costs for cleaning personnel as well as psychological costs for residents who feel disturbed by litter in this area. In this study, we test instruments to reduce littering in these waste disposal areas in a cost-effective way. We test four different nudges in this study. Currently, there is little evidence on how best to engage inhabitants of those community houses to preserve cleanliness in the shared waste disposal areas. In a randomized controlled trial, we test four interventions in around 560 waste disposal areas in over 90 different community houses. In a control group, there will be no poster and everything as is. The interventions are posters that will be placed above the garbage containers. Besides two classical nudges that work with pictures of landscapes or watching eyes and on a more subconscious level (system 1), there will be two posters focusing on raising awareness for the injunctive norm and the negative monetary consequences of littering (system 2). Our outcome variable is the tidiness/messiness of the waste disposal areas. We shoot pictures three times; before, shortly after hanging up the posters and after a couple of weeks. This way, we have a proxy on messiness at the baseline level, short-term effects, and long-time effects of the different interventions. The four treatments allow as to compare not only the intervention group to the control group but also make comparisons concerning effectiveness across different interventions.
External Link(s)
Registration Citation
Citation
Gangl, Katharina, Kerstin Grosch and Anna Walter. 2020. "Nudging to reduce littering in waste disposal areas – A field experiment in Austria’s community houses." AEA RCT Registry. June 30. https://doi.org/10.1257/rct.6108-1.0.
Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2020-07-13
Intervention End Date
2020-09-04
Primary Outcomes
Primary Outcomes (end points)
Outcome variable: floor_rating
Description of the outcome variable: Independent research assistants rate the floor pictures of the waste disposal areas (the treatment is not visible on the picture); the rating is based on perception from 1 to 7 whereas 1 indicates a sparkling clean floor and 7 a complete mess. With the numbers in between the research assistants can grade based on a pre-defined categorization. We employ two independent research assistants and take the average of the two floor ratings for the analysis.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
This field experiment tests an intervention to reduce littering in waste disposal areas in community houses in Vienna/Austria. Community houses differ in size from about 20 apartments in some houses to over 2000 apartments in other houses. The inhabitants take away their garbage bags in shared waste disposal areas. Waste disposal areas in community houses are often littered. This problem causes monetary costs for cleaning personnel as well as psychological costs for residents who feel disturbed by litter in this area. In this study, we test instruments to reduce littering in these waste disposal areas in a cost-effective way. We test four different nudges in this study. Currently, there is little evidence on how best to engage inhabitants of those community houses to preserve cleanliness in the shared waste disposal areas. In a randomized controlled trial, we test four interventions in around 560 waste disposal areas in over 90 different community houses. In a control group, there will be no poster and everything as is. The interventions are posters that will be placed above the garbage containers. Besides two classical nudges that work with pictures of landscapes or watching eyes and on a more subconscious level (system 1), there will be two posters focusing on raising awareness for the injunctive norm and the negative monetary consequences of littering (system 2). Our outcome variable is the tidiness/messiness of the waste disposal areas. We shoot pictures three times; before, shortly after hanging up the posters and after a couple of weeks. This way, we have a proxy on messiness at the baseline level, short-term effects, and long-time effects of the different interventions. The four treatments allow as to compare not only the intervention group to the control group but also make comparisons concerning effectiveness across different interventions.
Experimental Design Details
Not available
Randomization Method
The service agent for the community homes provided us with a list of 98 community houses. We randomize the treatments within community houses. We assign a unique number to each waste disposal area that identifies the community house and the specific waste disposal area. In the list, we sort the waste disposal areas by community houses and assign the treatment randomly. For this, we use a random number generator by the software excel between 1 and 5 whereas each number identifies one of the four treatment groups or the control group. We stratify by outdoor or indoor waste disposal area since we suspect that the effectiveness of the interventions may be heterogeneous across the two conditions. To ensure a balanced sample concerning treatment allocation, we kept updating the randomization until a distribution test (chi2) signaled that treatment conditions are assigned randomly across indoor and outdoor waste disposal areas.
Randomization Unit
We randomized within community houses and stratified by indoor/outdoor waste disposal areas.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
about 95 community houses
Sample size: planned number of observations
about 455 waste disposal areas
Sample size (or number of clusters) by treatment arms
about 90 waste disposal areas in each treatment group and in the control group, respectively.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
IHS Kommission zur Behandlung von Fragen der Ethik und wissenschaftlichen Integrität
IRB Approval Date
2020-06-30
IRB Approval Number
CSE005_2020_IA
Analysis Plan

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