The Effect of Feedback on recycling performance: a field experiment

Last registered on May 18, 2022

Pre-Trial

Trial Information

General Information

Title
The Effect of Feedback on recycling performance: a field experiment
RCT ID
AEARCTR-0009333
Initial registration date
May 17, 2022

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
May 18, 2022, 5:21 PM EDT

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

Locations

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Primary Investigator

Affiliation
University of the Balearic Islands

Other Primary Investigator(s)

PI Affiliation
University of the Balearic Islands
PI Affiliation
University of the Balearic Islands
PI Affiliation
Public University of Navarre

Additional Trial Information

Status
On going
Start date
2022-01-03
End date
2023-12-31
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Abstract
We designed a randomized field experiment to evaluate the effectiveness of feedback provision to promote recycling. We can observe individual real-time data on bio-waste recycling thanks to the introduction of a system of electronic bins in a Spanish densely populated city. We exploit these data to evaluate the impact of providing feedback on participation in waste sorting. The recruitment of participants was implemented by a team of environmental educators who has direct interaction with citizens.

In the control group, the subjects receive only one piece of information: A reminder about the recycling program. In the treatment group, the subjects receive two pieces of information: the reminder about the recycling program (as in the control group) and a report of past recycling performance of the household. In this way, one group receives information about its own recycling performance and the other does not.
External Link(s)

Registration Citation

Citation
Alonso-Pauli, Eduard et al. 2022. "The Effect of Feedback on recycling performance: a field experiment." AEA RCT Registry. May 18. https://doi.org/10.1257/rct.9333
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Experimental Details

Interventions

Intervention(s)
We designed a randomized field experiment to evaluate the effectiveness of providing feedback about its past recycling performance to promote waste sorting . The intervention is conducted in a Spanish densely populated city where a system of electronic bins was introduced for separating bio-waste.

A team of environmental educators provides information on bio-waste recycling and invites citizens to participate in our study. The information received by the households included how to use the bin, where to find a container, what types of waste are disposed of, and what types are not disposed of in that particular bin etc.

Once the informative sessions provided by the team of educators finish, we randomize the subjects using a computer, assigning them to a control group (no feedback) or to the treated group (feedback). The intervention consists of sending correspondence to those that agree to participate in the study. The difference between the treated and the control group consists of the information received.
- The group without feedback (control) receives general information about the program and a reminder about the information received from the environmental educators.
- The group with feedback (treated) receives general information about the program and a reminder about the information received from the environmental educators as well as information about its past recycling performance during the last 17 weeks.

We will evaluate the treatment effect by exploiting real-time data on the use of bio-waste bins.
Intervention Start Date
2022-05-17
Intervention End Date
2022-05-22

Primary Outcomes

Primary Outcomes (end points)
- %Weeks: proportion of weeks the container is used at least once
- # Uses: weekly average number of uses of the container
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We designed a randomized field experiment to evaluate the effectiveness of providing feedback to promote recycling. We are exploiting real-time microdata on bio-waste disposals to evaluate the intervention. The fieldwork for recruiting participants was executed by a team of environmental educators. The study was implemented in Palma (Balearic Islands, Spain). The educators were present at different informational points in the area of the study. The educators inform about the recycling program, provide households with a free recycling kit, and invite citizens to participate in the study.

We randomized the subjects with a computer, assigning them to a control group (no feedback) and to a treatment group (feedback). The intervention consists in sending correspondence to participants with different information:
- The control group receives general information about the program and a reminder about the information from the environmental educators.
- The treatment group receives general information about the program and a reminder about the information received from the environmental educators (as the control group). They also receive information about their environmental performance, measured according to the weekly uses of bio-waste bins.

Importantly, participating households have already participated in a previous intervention consisting in being offered monetary incentives to recycle (see trial AEARCTR-0006702). By the time this intervention is implemented monetary incentives to recycle are over and subjects are aware of that. Thus, in the current intervention, two mechanisms are combined: i) prior monetary incentives and ii) providing feedback to the household about their recycling performance.
According to this double intervention, the provision of feedback was randomized within each pre-existing experimental condition (monetary incentives to recycle and no monetary incentives to recycle). Summing up, we aim to analyze the effect of providing feedback and its interaction with the preceding monetary intervention. This results in a 2x2 design with the following 4 experimental groups:
Among those that in the first intervention were not treated :
(1) No monetary incentives and No feedback: half of the households receive a leaflet with general information about the introduction of the installation of the biowaste bin and a reminder of the information given by the educators.*
(2) No monetary incentives and Feedback: The remaining half of the households of the no monetary incentives group receive the same exact information (general information about the program) and additionally each household receives information about its recycling performance (to be described below)
Among those that in the first intervention were treated (the monetary incentives group):
(3) Monetary incentives and No feedback: half of the households receive a leaflet with general information about the introduction of the installation of the biowaste bin and a reminder of the information given by the educators.
(4) Monetary incentives and Feedback: The remaining half of the households of the commitment group receive the same exact information (general information about the program) and additionally they receive information about its recycling performance (to be described below)

The feedback about the recycling performance of the household was generated according to the proportion of weeks that the household made use of the recycling bins. The weeks included in the computation of this proportion extend from January 3rd 2022 to May 1st 2022 (both included). This was categorized in the following way for producing the feedback:

a) Satisfactory (green letters): whenever the household recycles at least 15 weeks out of 17.
b) Could be better (orange letter): whenever the household recycles between 11 and 14 weeks out of 17.
c) Unsatisfactory (light red): whenever the household recycles between 3 and 10 weeks out of 17.
d) Very unsatisfactory (dark red): whenever the household recycles 2 or fewer weeks out of 17.

The categorization includes a text in the corresponding color (Very satisfactory, Satisfactory, Unsatisfactory, and Very unsatisfactory) together with a colored smiley (see document attached) where the category assigned to the household was enlarged and highlighted whereas the other categories were lighter and smaller. Finally, a motivational sentence accompanied each of the categories. How the different categories were constructed was included in the letter as a footnote.


Recruitment period:
Recruitment of participating households is the one from trial ( AEARCTR-0006702) and took place between November 2020 and November 2021.

Intervention evaluation period:

The correspondence will be sent on May 18th. The households are expected to receive the letters between the 19th and 22nd of May (we incorporate a few letters with no information to our own addresses to check the arrival date)
The direct effect of the intervention will be evaluated using the real-time data from bio-waste bins from the week starting next Monday after receiving the letters until January 1st, 2023. Weeks after January 1st, 2023 can also be used if the effect is longer than this period.

Data prior to recruitment time will be used for pre-treatment balancing tests.

Place of the intervention: Palma (Balearic Islands, Spain)
Experimental Design Details

Randomization Method
In the preceding monetary intervention (trial AEARCTR-0006702) subjects were randomly assigned in alternation upon order of arrival at the information desk. That is, if the first citizen recruited on a given day was assigned to the monetary incentives group, the one that immediately followed was assigned to the no monetary incentives group.

For the present feedback intervention randomization was stratified within each experimental group in the preceding intervention, resulting in a 2x2 design. The randomization within each group was done by a computer with 50% in each group receiving no feedback and 50% receiving feedback.
Experimental Design Details
Not available
Randomization Method
Household level
Randomization Unit
Household level
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
0
Sample size: planned number of observations
1600
Sample size (or number of clusters) by treatment arms
1600 households. 4 treatment arms (approximately 25% of the observations in each treatment arm)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB

Institutional Review Boards (IRBs)

IRB Name
Comité de Etica de la Investigación
IRB Approval Date
2020-02-07
IRB Approval Number
128CER19