The roles of social norms and economic reasoning in shaping support for carbon pricing

Last registered on August 18, 2022


Trial Information

General Information

The roles of social norms and economic reasoning in shaping support for carbon pricing
Initial registration date
August 09, 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
August 18, 2022, 2:32 PM EDT

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



Primary Investigator

University of Oxford

Other Primary Investigator(s)

PI Affiliation
University of Oxford

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
In many countries, carbon pricing policies have not been implemented to an extent advocated by economists, partly due to fear of consumer and voter backlash. In this study, we conduct an online survey experiment to investigate determinants of support for (or opposition to) carbon pricing policies in the United States. Furthermore, we provide information through video interventions and investigate whether this can increase policy support. In particular, we focus on the roles of perceived social norms about climate action as well as reasoning about the economic mechanisms and impacts of carbon pricing. The use of different video interventions helps us shed light on several questions. Does policy support respond more strongly to norm-based appeals or to the perceived merit of a policy? Is there heterogeneity in which people are influenced more strongly by which type of information? Can norm-based interventions make individuals more receptive to information about the merits of a policy?
External Link(s)

Registration Citation

Fang, Ximeng and Stefania Innocenti. 2022. "The roles of social norms and economic reasoning in shaping support for carbon pricing." AEA RCT Registry. August 18.
Experimental Details


We will include two different information interventions in the form of animated explainer videos. The first intervention informs subjects (truthfully) about descriptive social norms towards climate action in the United States. The second intervention explains, in simple terms, the economic mechanisms and consequences of carbon pricing with lump-sum cash transfers.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
An incentivized donation decision to an environmental organization that advocates for carbon pricing in the United States, as well as stated support for carbon pricing
Primary Outcomes (explanation)
Subjects will have the decision to split $100 between themselves and two environmental organizations. One of the organizations will be a bipartisan group that advocates for carbon pricing in the United States (Climate Leadership Council), while the other environmental organization will not be related to carbon pricing. This decision is incentivized by randomly implementing it for a random subset of subjects.

In addition to the incentivized donation choices, we will also look at stated level of support for introducing carbon pricing (with uniform cash transfers) as a policy in the United States on a 4-point Likert scale (strongly support, somewhat support, somewhat oppose, strongly oppose).

Secondary Outcomes

Secondary Outcomes (end points)
Donation to the another environmental organization; stated support for other climate policies; beliefs about mechanisms of carbon pricing; general environmental attitudes
Secondary Outcomes (explanation)
Participants will also have the chance to donate to a second environmental organization whose work is not connected to carbon pricing (e.g., the National Wildlife Federation). We will make use of this second donation option to assess extensive margin (i.e., general pro-environmental attitudes) versus intensive margin (i.e., support specifically for carbon pricing) effects of our interventions, as well as potential spillover effects.

As additional outcome variables, we will include stated support for the U.S. carbon neutrality goals and other climate policies on discrete scales. These measures will be collected after the video interventions. Furthermore, we assess the effects that the videos exert on subjects’ general environmental attitudes and their reasoning about carbon pricing (mechanisms, effectiveness, distributional effects, economic impacts, etc.) through Likert scale questions. We will also assess the effect of our videos on posterior beliefs about social norms about carbon neutrality in the United States on continuous scales.

Experimental Design

Experimental Design
Subjects are randomly assigned to three different informational video interventions and a control group. Everyone (including those in the control group) sees a brief animated video that explains how anthropogenic carbon emissions contribute to climate change and that introduces the concept of carbon neutrality. Subjects in the treatment groups will receive additional information, as described below.

i) Norm treatment: The first treatment expands the initial animated video by further informing participants of descriptive social norms. In particular, participants will be (truthfully) informed that, according to a representative survey by the Pew Research Centre, 69% of adults in the U.S support the country’s carbon neutrality goals.

ii) Policy treatment: The education treatment consists of an additional educational video that explains, in simple terms, the economic mechanisms of carbon pricing and its distributional effects when revenues are redistributed in the form of lump-sum cash transfers.

iii) Norm+Policy treatment: This treatment combines the information received in the norms video treatment as well as the policy video treatment.
Experimental Design Details
Randomization Method
Randomization through online survey platform
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
3000 individuals
Sample size: planned number of observations
3000 individuals
Sample size (or number of clusters) by treatment arms
750 Control, 750 Norm treatment, 750 Policy treatment, 750 Norm+Policy treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
14.5 percent of a standard deviation

Institutional Review Boards (IRBs)

IRB Name
Central University Research Ethics Committee (CUREC) of the University of Oxford
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials