Fair Cooperation

Last registered on June 24, 2024


Trial Information

General Information

Fair Cooperation
Initial registration date
June 12, 2024

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
June 24, 2024, 1:41 PM EDT

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


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Primary Investigator

University of Kent

Other Primary Investigator(s)

PI Affiliation
Durham University

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Our study investigates the impact of redistribution and its perceived fairness on individual cooperation. In a controlled experiment, participants are randomly allocated to groups of four individuals, with each group subject to varying treatment conditions. These groups are characterized by distinct redistribution rules and levels of meritocracy associated with the incentivized tasks they undertake. The impact of these treatments on cooperation is subsequently measured using a public goods game. We hypothesize that groups subjected to higher levels of redistribution exhibit increased cooperation, i.e., higher levels of contribution. Moreover, this effect tends to diminish if the fairness of the redistribution is perceived as low. The research aims to shed light on how redistribution systems can shape individual cooperative behaviour and to explore the underlying mechanisms of any such relationship.
External Link(s)

Registration Citation

Guan, Rui and Andis Sofianos. 2024. "Fair Cooperation." AEA RCT Registry. June 24. https://doi.org/10.1257/rct.13588-1.0
Experimental Details


In the experiment, participants are randomly assigned to one of four treatment conditions. These conditions are defined by unique combinations of two levels of redistribution rules—low tax and high tax—and two levels of task meritocracy—low and high. To be specific, the conditions are as follows: (1) Low Tax, Low Meritocracy; (2) High Tax, Low Meritocracy; (3) Low Tax, High Meritocracy; and (4) High Tax, High Meritocracy. In each condition, participants engage in a task that follows the same format but varies in tax and meritocracy levels. After completing this task, participants of the same treatment condition are randomly matched in groups of four members. A predetermined percentage of each member's earnings, referred to as the tax, is collected based on the assigned treatment. This tax is pooled and evenly distributed among all group members. Participants' earnings in the tasks are determined by their performance and redistribution outcomes.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Our primary outcomes include both individual and group-level investments in a public goods game. These investments are examined in both a one-shot scenario and across repeated interactions, under different treatment conditions.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Our secondary outcomes include individual perceived fairness regarding the redistribution of their earnings in the meritocracy tasks.
Secondary Outcomes (explanation)
Participants are asked to rate their perceptions of fairness regarding their redistribution outcomes on a scale from 0 to 10.

Experimental Design

Experimental Design
The experiment is designed to be conducted on the platform Qualtrics, with participants recruited through Prolific. It consists of three parts, where participants engage in incentivized problem-solving tasks and economic decision-making scenarios. In the first part, participants undertake an incentivized task characterized by distinct redistribution rules and meritocracy levels based on their assigned treatment conditions. In the second part, they participate in a one-shot public good game to assess immediate cooperative behavior, without receiving any feedback from this game. In the third part, participants engage in an eight-round repeated public good game with feedback to assess cooperation dynamics across repeated interactions. Finally, participants provide information regarding their perception of fairness regarding their redistribution outcomes in the first part, as well as their personality traits and demographic characteristics.
Experimental Design Details
Not available
Randomization Method
The randomization is implemented by Qualtrics.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
160 groups.
Sample size: planned number of observations
640 individuals (4 per group).
Sample size (or number of clusters) by treatment arms
40 groups (160 individuals) in each treatment condition.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
With the planned sample size and a significance level of 0.05 and power of 0.80, our study is designed to detect effect sizes as small as 0.31 for participants' investments in the group project when comparing any two treatment arms at the individual level, and as small as 0.63 at the group level.

Institutional Review Boards (IRBs)

IRB Name
Business Faculty Ethics Committee, Durham University Business School
IRB Approval Date
IRB Approval Number