Assessing the Impact of Carbon Footprint Labels on Food Choices: A Longitudinal Study of Stagged Trials

Last registered on September 12, 2024
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Pre-Trial

Trial Information

General Information

Title
Assessing the Impact of Carbon Footprint Labels on Food Choices: A Longitudinal Study of Stagged Trials
RCT ID
AEARCTR-0014306
Initial registration date
September 04, 2024

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
September 12, 2024, 5:42 PM EDT

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

Locations

Country
China
Region
Kunshan, Jiangsu

Primary Investigator

Name
Ziqian Xia
Affiliation
Tongji University
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Other Primary Investigator(s)

PI Name
Helene Gu
PI Affiliation
Duke Kunshan University
Contact Investigator

Additional Trial Information

Status
In development
Start date
2024-08-21
End date
2025-06-01
Keywords
Behavior, Environment & Energy, Health
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
This study aims to evaluate the impact of carbon footprint labels on student food choices at an university's canteen through a longitudinal observational design. The intervention involves the phased introduction of carbon footprint labels in one restaurant within the canteen. The labeling will be implemented in stages, progressing from basic carbon emission numbers to more detailed environmental connections, to assess the influence of varying levels of labeling on purchasing behavior.

The primary outcome will be the percentage change in the selection of low-carbon footprint meals versus high-carbon footprint meals. Secondary outcomes include the total carbon footprint of meals purchased and the frequency of purchases of labeled versus non-labeled meals. By tracking actual meal purchases through the university's backend consumption records, the study seeks to provide a robust analysis of how carbon footprint labeling affects student choices over time.

The intervention will commence on September 2, 2024, and conclude on June 1, 2025. Data collection will involve baseline measurements prior to labeling, followed by the gradual introduction of labels, and concluding with post-intervention analysis. The study will use a regression framework and time-series analysis to examine changes in purchasing behavior, aiming to detect a 5% shift in the proportion of low-carbon meal selections.
External Link(s)

Registration Citation

Citation
Gu, Helene and Ziqian Xia. 2024. "Assessing the Impact of Carbon Footprint Labels on Food Choices: A Longitudinal Study of Stagged Trials." AEA RCT Registry. September 12. https://doi.org/10.1257/rct.14306-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2024-09-02
Intervention End Date
2024-12-31

Primary Outcomes

Primary Outcomes (end points)
The primary outcome will be the percentage change in the selection of low-carbon footprint meals versus high-carbon footprint meals.
Primary Outcomes (explanation)
We aim to determine whether the introduction of carbon footprint labels influences students to choose meals with lower carbon footprints. The outcome will be measured as the proportion of low-carbon meals purchased compared to high-carbon meals before and after the intervention with comparison between intervening restaurant and control restaurant.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes include the total carbon footprint of meals purchased in the canteen and the frequency of purchases of labeled versus non-labeled meals.
Secondary Outcomes (explanation)
The secondary outcomes will help assess the broader impact of carbon labeling on the overall carbon footprint associated with meal choices in the canteen and whether labeling increases awareness and shifts purchasing behavior even when some meals remain unlabeled.

Experimental Design

Experimental Design
The study will be conducted in one restaurant in the DKU canteen. Carbon footprint labels will be introduced in phases, allowing for a comparison of purchasing behavior between labeled and non-labeled restaurants over time.

The carbon label intensities will be implemented in a sequential order from least informative to most informative. This staggered approach allows for an assessment of the impact of each degree of labeling while controlling for associations formed by previous information presented.
Experimental Design Details
Not available
Randomization Method
The order of introducing the carbon footprint labels across the different restaurants is fixed and not randomized.
Randomization Unit
The analysis will still consider each individual carbon labeled menu as the unit of analysis to assess the impact of the labeling on purchasing behavior.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1-3 restaurant in the canteen will implement carbon footprint labels.
Sample size: planned number of observations
Over the course of the study, we estimate approximately 3000 individual meal purchases will be tracked.
Sample size (or number of clusters) by treatment arms
The study will have 2+ menu versions of carbon labeled menus, with more targeted labeling introduced in phases. For instance, the first menu has the raw numbers of g CO2 emitted, the second has a traffic light color code from low to high emission, the third has a connection between CO2e and the environment.
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

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