A theory of social norms

Last registered on February 24, 2022


Trial Information

General Information

A theory of social norms
Initial registration date
February 23, 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
February 24, 2022, 1:23 PM EST

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


Primary Investigator

Sciences Po & Paris School of Economics

Other Primary Investigator(s)

PI Affiliation
Ca' Foscari University of Venice

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 this paper, we aim to acquire a quantitative understanding of how individual decisions to take a particular action depend on the share taking that action in their immediate environment.
External Link(s)

Registration Citation

Rasooly, Itzhak and Roberto Rozzi. 2022. "A theory of social norms." AEA RCT Registry. February 24. https://doi.org/10.1257/rct.9013-1.0
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Whether individuals choose to wear a face mask.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
See below.
Experimental Design Details
The experimental design is as follows:
1. A experimental subject enters a room and are greeted by four experimenters.
2. Unbeknownst to the subject, the number of the room experimenters who are wearing a face mask has been randomised (so there are five treatments, corresponding to 0/4 masks, 1/4 masks, 2/4 masks, 3/4 masks, and 4/4 masks).
3. An experimenter asks the subject for some basic demographic information (e.g. their age).
4. Another experimenter asks them whether they would prefer 1) a single lottery ticket for an Amazon voucher 2) a gamble between 0 or 2 lottery tickets that first order stochastically dominates the single lottery ticket.
5. The individual leaves the room and the process repeats.
Randomization Method
Using Python.
Randomization Unit
See experimental design.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
We hope to obtain a sample of at least 500.
Sample size: planned number of observations
See above.
Sample size (or number of clusters) by treatment arms
The sample will be split between 5 treatment groups.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
University of Oxford
IRB Approval Date
IRB Approval Number


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