The effect of social norms on preferences and willingness-to-pay for green investments

Last registered on April 06, 2026

Pre-Trial

Trial Information

General Information

Title
The effect of social norms on preferences and willingness-to-pay for green investments
RCT ID
AEARCTR-0018218
Initial registration date
March 31, 2026

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
April 06, 2026, 7:54 AM 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 Vaasa

Other Primary Investigator(s)

PI Affiliation
Pellervo Economic Reseach
PI Affiliation
Pellervo Economic Reseach
PI Affiliation
Pellervo Economic Reseach
PI Affiliation
University of Vaasa
PI Affiliation
Pellervo Economic Reseach

Additional Trial Information

Status
In development
Start date
2026-04-06
End date
2026-04-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
In this study we investigate the effect of social norms on investment decisions, that is, whether providing information on others' views has an effect on the preferences toward green investments and if it affects the willingness to pay for green investments.
External Link(s)

Registration Citation

Citation
Gråsten, Emilia et al. 2026. "The effect of social norms on preferences and willingness-to-pay for green investments." AEA RCT Registry. April 06. https://doi.org/10.1257/rct.18218-1.0
Experimental Details

Interventions

Intervention(s)
The intervention consists of two stages. In the first stage, respondent’s beliefs regarding three statements are elicited. In the second stage, participants in the treatment groups receive information regarding the views of the broader population. The control group receives no information.
Intervention Start Date
2026-04-06
Intervention End Date
2026-04-30

Primary Outcomes

Primary Outcomes (end points)
The primary objective of this study is to evaluate the impact of the intervention on preferences for green investing and the willingness to pay (WTP) for funds focused on green investments.
Primary Outcomes (explanation)
We estimate WTP estimates for each of the treatment groups and the control group and compare the WTP estimates.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Our design combines a randomized controlled trial (RCT) with a discrete choice experiment (DCE). First, the survey starts with a screening question: “Do you have investments in stocks or in funds?”. Only participants who have such investments proceed to the main survey. We aim for sample size of approximately 2000 participants.

The survey starts with an intervention that closely follows the intervention conducted by Andre et al. (2024). First, the beliefs regarding three statements are elicited from all participants (see Intervention section for a detailed description of these statements). Participants are then randomly assigned to one of three treatment groups (T1, T2, T3) or to a control group. Groups T1 through T3 receive information regarding how respondents answered in a previous survey conducted in March 2025. The survey had 2,001 respondents and the sample was representative by age, gender, and regions. Each group receives information on slightly different statements, while the control group receives no information.

Following the intervention, we conduct the DCE to estimate the choice probabilities. For the DCE we use blocked D(B)-efficient design consisting of three blocks. Participants in each treatment group are randomly assigned to one of these three blocks. Specifically, one-third (~166 participants) of each group is allocated to Block 1, one-third to Block 2, and one-third to Block 3. Participants face eight (8) hypothetical choice situations in which they choose their most preferred fund from three alternatives. Each alternative is characterized by several attributes (past return, management fee, risk, and fund’s focus). Because the choice tasks differ across blocks, there are 24 distinct choice situations in total.

After the DCE we present the belief elicitation question again to check the effectiveness of the intervention. For example, for participants in T1 we ask their beliefs regarding statement 1 (see Intervention section). Finally, we will conduct a post-experiment survey where we collect additional demographic and background information.

Andre, P., Boneva, T., Chopra, F., & Falk, A. (2024). Misperceived social norms and willingness to act against climate change. Review of Economics and Statistics, 1-46.
Experimental Design Details
Not available
Randomization Method
Randomization done by a computer by a survey company.
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
2000 participants
Sample size: planned number of observations
2000 participants
Sample size (or number of clusters) by treatment arms
500 in each treatment condition
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