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Last registered on May 04, 2018


Trial Information
General Information
Initial registration date
May 03, 2018
Last updated
May 04, 2018 11:37 AM EDT
Primary Investigator
Stockholm School of Economics
Other Primary Investigator(s)
Additional Trial Information
In development
Start date
End date
Secondary IDs
This is the analysis plan for a laboratory experiment conducted at the University of California San Diego. In the experiment which will be described in detail below, potential senders make a promise about how much they will give to the receiver in a dictator game. Based on the promises a receiver can select one of two potential senders to play the dictator game with. We investigate whether promises allow a selection of better senders and whether competition in promising leads senders to give more than they do in a regular dictator game controlling for any positive selection.
Firstly, we predict that different sender types do not separate by their promise such that no selection of better senders is possible. In addition, we expect most senders the same or a very similar promise, the modal promise to be equal or higher than the amount that gives both senders and receivers an equal amount.
Secondly, we predict that senders give away more in the promise than the dictator game, both for all participants and when restricting the analysis to those participants that are selected as senders.
External Link(s)
Registration Citation
Born, Andreas. 2018. "PROMISE COMPETITION ." AEA RCT Registry. May 04. https://doi.org/10.1257/rct.2952-1.0.
Former Citation
Born, Andreas. 2018. "PROMISE COMPETITION ." AEA RCT Registry. May 04. http://www.socialscienceregistry.org/trials/2952/history/29114.
Experimental Details
We run a laboratory experiment which is described in the experiment section.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
We are interested in (1) the level of promises participants make, (2) the amount of points participants give away in the promise game condition, (3) the amount of points participants give away in the dictator game condition. Finally in the selection decision of the participants.

Primary Outcomes (explanation)
For a more detailed description please refer to the attached pre-analysis plan.
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
In the laboratory experiment participants play a modified dictator game in which the receiver can select a sender based on the promises of the two potential senders. The game will be repeated with feedback. In addition participants play a regular dictator game. Both games will be played in random order. Both versions of the dictator game will include a multiplier of two. More details of the experiment and analysis will be made public after the experiment and analysis is conducted.
Experimental Design Details
The experiment consists of two parts. These parts are played in random order, i.e. in each session half of the participant starts with Part A and the other half starts with Part B. Part A In this part, two participants are matched. One will take the role as receiver and one as sender. Before these roles are randomly assigned both participants get to decide how they will split 100 points between herself and the receiver in case they become the sender. To that end they are asked to state the integer number of points they would like to pass on. The number of points that is passed on to the receiver is doubled for the receiver. We employ the strategy method and ask both participants to indicate the amount they would like to send to the receiver if they get randomly determined as sender. We denote the amount participant i decides to pass on to the receiver as d_i. In the end of the experiment, the computer randomly picks for each pair, who of the participants is to be a sender and implements their decision automatically. Part B This part is repeated ten times. We refer to a single repetition as ‘round’. At the beginning of each round all participants are randomly (re-)matched in groups of three. In each group one participant will take the role of a receiver and two participants will be senders. The receiver can choose which one of the two senders to play a dictator game with. The chosen sender becomes the sender in the dictator game with the receiver who made the selection choice. The sender gets an endowment of 100 points and decides how many points to pass on to the receiver. The number of points that is passed on to the receiver is doubled. The sender who is not chosen gets no points. We denote the amount participant i decides to pass on to the receiver in round t as s_it and the according promise p_it. This part employs the strategy method. Before the receiver makes her choice, all three participants are asked to enter the amount of points they would like to promise to the receiver if they get randomly determined as sender in the game. After all participants indicated their promise, they are asked on a separate screen to decide about the amount they want to send if they are selected by the receiver. After all participants made their sender-decisions, they are asked to make their decision in case they get randomly determined as the receiver in the end of the round. To that end, each participant sees the promises of the two other participants in his or her group and decides with which sender to he or she wants to select. After all participants make these decisions their roles (sender or receiver) are randomly assigned by the computer, the according decisions are implemented. In the end of each repetition the computer displays the two promises of the senders, the choice of the receiver, and the actual decision of the selected sender to all group members.
Randomization Method
We randomize by computer.
Randomization Unit
The individual participant.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
150 participants
Sample size (or number of clusters) by treatment arms
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)