Patron-Dictator Game: Strategic Interaction between Charities and Donors

Last registered on February 15, 2023


Trial Information

General Information

Patron-Dictator Game: Strategic Interaction between Charities and Donors
Initial registration date
December 09, 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
December 13, 2022, 11:19 PM EST

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

Last updated
February 15, 2023, 12:13 AM EST

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



Primary Investigator

Graduate School of Economics, Osaka University

Other Primary Investigator(s)

PI Affiliation
Research Institute for Socionetwork Strategies, Kansai University

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
In the charity market, donations are generally credence goods. In other words, in the charity market, there is an information asymmetry in that it is difficult for donors to know in advance the extent to which their donations improve recipients' welfare (charitable organizations retain this information). Thus, the dictator game, widely used to measure altruistic preference in laboratory experiments, may not correspond to real-world donation behavior because the recipient's welfare is visible.

This study makes a modified dictator game called the patron-dictator game that incorporates the role of charitable organizations. We conduct two games: the patron-dictator game and a standard dictator game in a lab experiment. Through these experiments, we examine two research questions: (1) the extent to which donation behavior in the Patron-Dictator game, which is similar to the real donation market, differs from that in the standard dictator game; (2) how donation information asymmetries affect donation behavior.
External Link(s)

Registration Citation

Kato, Hiroki and Youngrok Kim. 2023. "Patron-Dictator Game: Strategic Interaction between Charities and Donors." AEA RCT Registry. February 15.
Experimental Details


The patron-dictator game consists of a patron, a dictator, and a receiver. In this game, the patron and dictator make decisions sequentially and determine the allocation of gains among the three players (see analysis plan for detailed game structure).

In addition to conducting the simple dictator game (the DG treatment), we create the following two interventions regarding the order of decision-making of the patron and dictator in the patron-dictator game:

1. First-Moving Dictator (FD): The dictator move first, followed by the patron.
2. Second-Moving Dictator (SD): The patron move first, followed by the dictator.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
For consistency, we refer to the role of the dictator in the dictator game as a patron. Our primary outcome is amounts sent by a patron.
Primary Outcomes (explanation)
The patron in the two games corresponds to the donor in the real charity market. We compare donor behavior among three treatments.

Secondary Outcomes

Secondary Outcomes (end points)
1. Allocation of funds provided by patron between dictator and receiver in the FD and SD treatments
2. Receiver's gain
Secondary Outcomes (explanation)
The first secondary outcome corresponds to the behavior of charitable organizations in the real charity market. Since the FD and SD treatments reflect the presence or absence of information asymmetry about recipients' welfare in the charity market, we examine how asymmetric information affects the behavior of charities by comparing dictator's behavior between FD and SD treatments. The second secondary outcome is the receiver's welfare. We examine how asymmetric information and the presence of charitable organizations affect the recipient's welfare by comparing the receiver's gain among three treatments.

Experimental Design

Experimental Design
[Fixed] We schedule 9 sessions lasting 90 minutes per session over five days. We recruit up to 33 people per session (32 people per session with the DG treatment). In the beginning, participants take a quiz on the game structure (only FD and SD treatments). Next, they play a one-shot game repeatedly (10 rounds). We make at most 11 groups of three participants for the FD and SD treatments and up to 16 groups of two participants for the DG treatment. After each round, we randomly reassemble the groups and randomly change the roles. Finally, they take a survey of demographics and altruistic preferences.
Experimental Design Details
Not available
Randomization Method
[Fixed] We assign the DG treatment to the one session and the FD and SD treatments to the remaining 8 sessions. We equally randomize the two interventions at the session level to balance session dates and times.
Randomization Unit
[Fixed] Experimental session.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
[Fixed] 9 experimental sessions.
Sample size: planned number of observations
[Fixed] up to 1,040 groups
Sample size (or number of clusters) by treatment arms
[Fixed] 1. FD treatment: up to 440 groups (4 sessions)
[Fixed] 2. SD treatment: up to 440 groups (4 sessions)
[Fixed] 3. dictator game: up to 160 groups (1 sessions)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
[Added] Minimum detectable effect sizes are for a two-sided hypothesis test with statistical significance of 0.05 and statistical power of 0.8: 2.1 standard deviation (FD or SD vs. DG); 1.1 standard deviation (FD vs. SD). See the analysis plan in detail.

Institutional Review Boards (IRBs)

IRB Name
IRB, Research Institute for Socionetwork Strategies, Kansai University
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