An Experiment on Two-Person Social Choice

Last registered on March 30, 2023


Trial Information

General Information

An Experiment on Two-Person Social Choice
Initial registration date
March 22, 2023

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
March 30, 2023, 3:17 PM EDT

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



Primary Investigator

Sabanci University

Other Primary Investigator(s)

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Are there good mechanisms that a group of decision-makers can use to reach a joint decision on a set of alternatives? Applications range from project evaluations and committee decisions to the selection of arbitrators in conflict resolution. In practice, there is a range of mechanisms such as the highly popular Veto Rank mechanism. The related literature also proposes a number of mechanisms that are theoretically argued to be superior. In this project, we will run an experiment to compare these mechanisms in terms of efficiency and fairness, as well as how close the experimental subjects behave in relation to the equilibrium predictions.
External Link(s)

Registration Citation

Bas, Sonnur. 2023. "An Experiment on Two-Person Social Choice." AEA RCT Registry. March 30.
Experimental Details


We will invite Sabanci University students to experimental sessions where in each session, they will be paired to interact according to the rules of one of the aforementioned mechanisms
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Two-Person social choice over 5 alternatives
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Participants will be collected from among Sabanci University students based on voluntary participation. In one session, participants will play the game associated with the respective mechanism for 40 rounds, each time facing a different randomly assigned partner. In each round, participants will see several screens asking them to choose one or more options from among five available alternatives (called a, b, c, d, e). Each option will have a different payoff for a participant (and the two partners will have different payoffs from an option). At the beginning of each round, a player will be presented with a table informing her of her own payoffs as well as the payoffs of her partner. At the end of the experiment, one of the 40 rounds played will be randomly chosen for each player. A player’s payoff from the experiment will be her payoff from the randomly selected round plus her participation payoff
Experimental Design Details
Randomization Method
Randomization done in office by a compute
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
320 participants
Sample size: planned number of observations
About 320 participants and 40 rounds: 12800 observations
Sample size (or number of clusters) by treatment arms
The sample will be split approximately equally across the four treatment.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Sabancı University Research and Ethics Council
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information


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