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Why do Crowdinvestors invest? Survey and decision experiment

Last registered on July 20, 2021


Trial Information

General Information

Why do Crowdinvestors invest? Survey and decision experiment
Initial registration date
April 22, 2021

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 26, 2021, 10:42 AM EDT

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

Last updated
July 20, 2021, 11:45 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator

University of Essex

Other Primary Investigator(s)

PI Affiliation
University of Bremen

Additional Trial Information

Start date
End date
Secondary IDs
We run a field experiment / lab in the field experiment (online) with crowdfunders. The survey part of the experiment is asking for the reasons why investors use crowdfunding, rather than alternatives such as stocks, funds etc. The survey also elicits various demographics and risk and time preferences.

In an incentivized choice experiment, we then elicit data to determine why crowdfunders in particular invest in green projects. For details, see the attached document.

Subjects are randomized into a condition that completes the experiment first, or another condition that completes the survey first.
External Link(s)

Registration Citation

Hornuf, Lars and Christoph Siemroth. 2021. "Why do Crowdinvestors invest? Survey and decision experiment." AEA RCT Registry. July 20.
Sponsors & Partners

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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The key choice in the experiment is that between a 25 Euro voucher and a donation to one of 3 organisations g. We determine the willingness to accept the donation over the voucher via a BDM procedure. Thus, for every subject, we elicit WTA_g. The organisations are a carbon offset company, Greenpeace, and the Red Cross.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
See the attached pre-analysis plan.
Experimental Design Details
We will recruit active crowdfunders from the platform via email newsletters. The platform is sending regular newsletters, and has conducted a survey of its own before, so this is not unusual.

Subjects will go through a survey and a choice experiment. The order of these two elements is randomized at subject level. The core of the experiment is to elicit a willingness to accept a donation to one of 3 causes (two environmental, one social) over a 25 Euro voucher, which can be used on the homerocket crowdfunding platform. This choice is incentivized, as we will actually give subjects the voucher or make the donation on their behalf, according to their choice.

Since the voucher can only be invested in real estate projects, but not in green projects, the choice between the voucher (similar to cash or higher returns) or the green or social causes tells us what subjects truly care about in an incentivized way.

The donations go to one of three organisations:, Greenpeace, or the Red Cross Austria. The first two achieve environmental impact, the last achieves social impact. Thus, if subjects give up the voucher to let us make these donation, then this reveals their preference for environmental or social impact.

As we describe in the pre-analysis plan, these elicited willingnesses to pay then help us determine whether investors invest in green projects for their higher expected returns, their environmental impact, or their social impact.
Randomization Method
Randomization is determined by qualtrics' random number procedure.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
We aim for 400 completed surveys/experiments, and will send out email newsletter invitations until we reach this number.

We might get slightly more than 400, as qualtrics allows subjects who have started the survey to finish it. Thus, once we stop accepting new responses at 400, those who have already started can still finish.
Sample size: planned number of observations
400 subjects.
Sample size (or number of clusters) by treatment arms
400 subjects.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Ethics Sub Committee 3 of University of Essex
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?
Intervention Completion Date
May 03, 2021, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
May 03, 2021, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
399 crowdfunders
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
399 crowdfunders
Final Sample Size (or Number of Clusters) by Treatment Arms
399 crowdfunders
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Are investors willing to give up a higher return if the investment generates positive environmental impact? We investigate this question with a decision experiment among crowdfunders, where they choose between a higher return or environmental impact. Overall, 65% of investors choose environmental impact at the expense of a higher return for sufficiently large impact, 14% choose impact independent of the magnitude of impact, while 21% choose the higher return independent of impact. Combining the experimental data with historical investments, we find that investors allocate a larger share of funds to green projects if they value environmental impact more, and if they expect green projects to be more profitable. These findings suggest that investors have a preference for positive environmental impact, and satisfy it by investing in green projects. We further show that the preference for environmental impact is distinct from a preference for positive social impact. Finally, we introduce new survey measures of impact for future use, which are experimentally validated and predict field behavior.
Siemroth, Christoph and Hornuf, Lars, Do retail investors value environmental impact? A lab-in-the-field experiment with crowdfunders (July 14, 2021). Available at SSRN:

Reports & Other Materials

Study published in JEBO.
Siemroth, C., & Hornuf, L. (2023). Why Do Retail Investors Pick Green Investments? A Lab-in-the-Field Experiment with Crowdfunders. Journal of Economic Behavior & Organization, 209, 74-90.