Social information and waste disposal
Last registered on June 18, 2021

Pre-Trial

Trial Information
General Information
Title
Social information and waste disposal
RCT ID
AEARCTR-0007834
Initial registration date
June 18, 2021
Last updated
June 18, 2021 12:54 PM EDT
Location(s)
Region
Primary Investigator
Affiliation
Politecnico di Milano
Other Primary Investigator(s)
PI Affiliation
PI Affiliation
PI Affiliation
PI Affiliation
Additional Trial Information
Status
On going
Start date
2020-07-01
End date
2021-10-31
Secondary IDs
Abstract
We assess the impact of a social information program on the disposal of unsorted waste. We study a program implemented by an Italian multi-utility using an hybrid Pay-as-you-Throw collection system. Households are assigned a maximum number of solid waste units yearly and pay a fixed amount when the quantities are below such limit. For each unit exceeding the cap, customers pay per unit. We randomize customers into a treatment group which receives quarterly reports including information over the volume of unsorted waste compared to the average waste of similar customers living in the city, and a control group which receives nothing. Within the group of treated households receiving the report, half receives the standard report. The other half receives the report along with a clear reference to the disposal cap. This information allows treated customers to keep track of their performance against the cap, which is calculated on a yearly basis. We measure the main and heterogeneous treatment effects on the volume of unsorted waste and on the probability of passing the yearly threshold.
External Link(s)
Registration Citation
Citation
Bonan, Jacopo et al. 2021. "Social information and waste disposal." AEA RCT Registry. June 18. https://doi.org/10.1257/rct.7834-1.0.
Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2020-07-01
Intervention End Date
2021-06-30
Primary Outcomes
Primary Outcomes (end points)
1. Customer volume of solid waste disposal in the month
2. Probability of exceeding the yearly cap for solid waste disposal
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We evaluate the impact of a social information campaign through the design and launch of "Opower-style"home waste reports. The report kicked-off in July 2020 and is delivered by post and email to customersevery quarter, after the waste bill. The reference period of the report is the same of that reported in the bill.The report includes the following elements: 1. static neighbour comparison, 2. Cumulative solid waste disposal, 3. Dynamic feedback, 4. Access to waste collection centers.
The experimental design relies on the random assignment of two thirds of eligible customers to a treatment group which receives the report and one third to a control group, which does not. Within the group of treated households receiving the report, half receives the standard report as described above. The other half receives the report, as described above, along with a clear reference to the disposal cap, displayed in the cumulative solid waste disposal section. This information allows treated customers to keep track oftheir performance against the cap, which is calculated on a yearly basis. These customers also visualize an alert if the volume disposed in the quarter exceeds one fourth of the yearly cap assigned.
Experimental Design Details
Not available
Randomization Method
We follow a stratified individual level randomization procedure, to maximize ex-ante balance across the three experimental groups along a battery of important observable characteristics. Strata are obtained from the combination of the following variables:
- The disposal caps for unsorted waste in 2020
- The presence of any kind of benefit/deductible in terms of higher cap, due to the presence of children or health needs in the household (at the time of data extraction, i.e. April 2020)
- House size above the median
- Access to waste collection centres in 2019
- Having a valid e-mail access (hence possibly receiving the report by email vs by post)


We exclude strata with less than ten observations. We end up with 96 strata. Within each stratum, we sort customers by baseline unsorted waste disposal volume (in the period April 2019-March 2020) and assign adjacent customers to treatments and control group.
Randomization Unit
Individual/user level randomization
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
no clusters
Sample size: planned number of observations
About 54,150 users
Sample size (or number of clusters) by treatment arms
About 18,050 users in each of the three treatment arms (two treatments and one control group)
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
Analysis Plan
Analysis Plan Documents
PAP

MD5: 0793c327c98b112c46396d7b0426f72a

SHA1: 7a54aea40f1f5d430a39fe044a01236dc03c50db

Uploaded At: June 18, 2021