The effectiveness of personalised versus generic information in changing behavior: Evidence from an indoor air quality experiment

Last registered on July 26, 2021

Pre-Trial

Trial Information

General Information

Title
The effectiveness of personalised versus generic information in changing behavior: Evidence from an indoor air quality experiment
RCT ID
AEARCTR-0007980
Initial registration date
July 19, 2021
Last updated
July 26, 2021, 10:27 AM EDT

Locations

Region

Primary Investigator

Affiliation
Ecole Normale Supérieure

Other Primary Investigator(s)

PI Affiliation
LEDa, Université Paris-Dauphine, Université PSL, IRD, CNRS, 75016 Paris, France
PI Affiliation
CEPREMAP, Paris
PI Affiliation
LNC², Département d’études cognitives, Ecole normale supérieure, Université PSL, INSERM, 75005 Paris, France

Additional Trial Information

Status
Completed
Start date
2019-08-01
End date
2020-03-31
Secondary IDs
Abstract
While indoor air pollution is one of the leading causes of morbidity and mortality worldwide, its sources and impacts are largely misunderstood by the public. In a randomized controlled trial including 281 households in France, we test two interventions aimed at raising households' awareness of indoor pollutants and ultimately improving indoor air quality. While both generic and personalized information increase awareness, only personalised information is successful in shifting behavior and decreasing indoor air pollution - by 20% compared to the control group. Heterogeneous treatment effects show that this effect is concentrated in the most polluted households at baseline.
External Link(s)

Registration Citation

Citation
Abdel Sater, Rita et al. 2021. "The effectiveness of personalised versus generic information in changing behavior: Evidence from an indoor air quality experiment." AEA RCT Registry. July 26. https://doi.org/10.1257/rct.7980-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
The interventions

Both interventions involved mailing eight leaflets to households. All households participating in the study were equipped with air quality monitors. In order to discern the impact of personalised feedback from generic information provision, we distinguish two treatments.

1) The Information Treatment
In the Information treatment, we sent households informational leaflets on different PM2.5 emitting activities, their associated health risks, as well as tips to improve indoor air quality. Each leaflet was composed of a cover page containing an illustration and a catchy slogan, a page containing infographics on sources of indoor air pollution and health risks, and a page detailing good practices.

2) The Information + Personalised Emission Profile Treatment
The second treatment provided households with the same generic information as in the Information Treatment, but added people's personalised emission profile based on their real PM2.5 emissions over the last week. Using data from the air quality monitors, the households' indoor PM2.5 concentration was measured every 5 minutes and represented on a figure along with the date and hour of the major pollution peaks. The Personalised Emission Profile also included a ranking of the household in terms of air quality compared to households in the control group.
Intervention Start Date
2020-01-06
Intervention End Date
2020-03-09

Primary Outcomes

Primary Outcomes (end points)
Average household indoor PM2.5 levels
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Perception and knowledge about air pollution
Perception, knowledge and attitude about wood burning
Self-reported polluting activities
Secondary Outcomes (explanation)
Perception and knowledge about air pollution
The baseline and endline questionnaires included questions about the household's perceived indoor and outdoor air quality, knowledge of main indoor and outdoor sources of pollution, and perceived impact of air pollution on health.

Perception, knowledge and attitude about wood burning
The baseline and endline questionnaires included a set of variables reflecting the household's perception on the contribution of wood burning to indoor pollution, knowledge of good wood burning practices, attitude towards wood burning regulation, the pleasure when lighting a fire, as well as the intention to change wood burning equipment in the future.

Self-reported polluting activities
We collected information about households' self-reported polluting activities, such as the frequency of wood burning over past winter, its intended use in the future, and the number of times they engaged into smoking, wood burning, candles, incense, and dusting over the past week.

Experimental Design

Experimental Design
To measure the differential effect of the two treatments, 281 households received a micro air quality monitor and were asked to plug it in their living room. Using a baseline questionnaire, households were stratified by the presence of a smoker in the household and then matched into the best triplets according to their average weekly PM2.5 levels at baseline (Both smoking and baseline indoor PM2.5 levels highly predict indoor air pollution post-treatment). This resulted in 94 triplets. Within each triplet, households were randomly assigned to one of 3 groups; 94 households received the Information treatment, 94 households received the Information + Personalised Emission Profile treatment, and 94 households received no leaflets and served as the control group. At the end of the intervention, the control households were given access to the informational campaign, and both the Information and control groups received their indoor air quality Personalised Emission Profile for the entire intervention period.
Experimental Design Details
To measure the differential effect of the two treatments, 281 households received a micro air quality monitor and were asked to plug it in their living room. Using a baseline questionnaire, households were stratified by the presence of a smoker in the household and then matched into the best triplets according to their average weekly PM2.5 levels at baseline (Both smoking and baseline indoor PM2.5 levels highly predict indoor air pollution post-treatment). This resulted in 94 triplets. Within each triplet, households were randomly assigned to one of 3 groups; 94 households received the Information treatment, 94 households received the Information + Personalised Emission Profile treatment, and 94 households received no leaflets and served as the control group. At the end of the intervention, the control households were given access to the informational campaign, and both the Information and control groups received their indoor air quality Personalised Emission Profile for the entire intervention period.
Randomization Method
Randomization in office by a computer
Randomization Unit
household
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
282 households
Sample size: planned number of observations
282 households
Sample size (or number of clusters) by treatment arms
94 households received the Information treatment, 94 households received the Information + Personalised Emission Profile treatment, and 94 households received no leaflets and served as the control group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
1.2 micrograms/m3. sd: 3.798, percentage change: 21%
IRB

Institutional Review Boards (IRBs)

IRB Name
Paris School of Economics
IRB Approval Date
2019-07-25
IRB Approval Number
2019 016
Analysis Plan

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Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
Yes
Intervention Completion Date
March 09, 2020, 12:00 +00:00
Data Collection Complete
Yes
Data Collection Completion Date
March 31, 2020, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
282 households
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
282 households
Final Sample Size (or Number of Clusters) by Treatment Arms
94 households received the Information treatment, 94 households received the Information + Personalised Emission Profile treatment, and 94 households received no leaflets and served as the control group.
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
No
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials