What is fair? Experimental evidence on the trade-off between equality and reward

Last registered on February 23, 2023


Trial Information

General Information

What is fair? Experimental evidence on the trade-off between equality and reward
Initial registration date
November 16, 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
November 18, 2022, 12:28 PM EST

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

Last updated
February 23, 2023, 9:27 AM EST

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



Primary Investigator

University of Hohenheim

Other Primary Investigator(s)

PI Affiliation
University of Hohenheim
PI Affiliation

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Meritocracy implies paying people according to their performance. It thereby comprises two principles: (i) paying individuals with higher performance more (reward) and (ii) paying people with equal performance equally (equality). While the literature has mainly focused on the reward dimension, we lack evidence on the importance that people attach to equality. This is surprising given that the theoretical social justice literature has pointed out that in many circumstances it is impossible to fulfill both principles at the same time. We empirically investigate individuals’ fairness preferences regarding both reward and equality. In particular, we describe the importance of equality if individuals cannot simultaneously pursue both principles. Furthermore, we explore individuals’ willingness to pay for fulfilling the equality and reward principles by experimentally varying the cost of doing so. To this end, we implement a pre-registered experiment in a survey among a representative US sample.
External Link(s)

Registration Citation

Dwenger, Nadja, Ingrid Hoem Sjursen and Jasmin Vietz. 2023. "What is fair? Experimental evidence on the trade-off between equality and reward." AEA RCT Registry. February 23. https://doi.org/10.1257/rct.10425-2.1
Experimental Details


We administer an online survey among a representative sample of the US population to elicit individuals’ preferences for reward and equality. We randomize respondents into three treatment groups that vary with respect to the costs of implementing equality and reward.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The main outcome of interest is the choice of the participant, i.e., whether (s)he redistributes to implement the reward principle or to implement the equality principle.
Primary Outcomes (explanation)
Based on the participants’ decision we will create an indicator that equals one if the participant prefers equality to reward.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Our main experiment is an online experiment with a spectator design on a representative sample of US citizens. There are two types of participants: spectators and workers. Workers complete real effort assignments. Subsequently, spectators make a choice that has monetary consequences for workers.
Experimental Design Details
Randomization Method
Randomization by survey software
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Not applicable as no clustering.
Sample size: planned number of observations
Pre-test with 400 spectators, who take two different decisions each. Main experiment with 1,500 spectators, who make two decisions each = 3,000 decisions.
Sample size (or number of clusters) by treatment arms
400 spectators in Pre-Test; 500 spectators in control; 500 spectators in treatment 1 (Costly Equality); 500 spectators in treatment 2 (Costly Reward)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Ethics Committee Hohenheim
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?
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