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Social exclusion
Last registered on July 24, 2019


Trial Information
General Information
Social exclusion
Initial registration date
July 19, 2019
Last updated
July 24, 2019 11:42 AM EDT
Primary Investigator
University of Cologne
Other Primary Investigator(s)
Additional Trial Information
On going
Start date
End date
Secondary IDs
In this project, we investigate whether social exclusion affects performance. Social
exclusion is psychologically costly, and could also signal low ability. We incorporate
these two aspects of social exclusion in a model that shows that (i) irrespective of the
cause of social exclusion, being excluded decreases subsequent performance, (ii) the
possibility of future social exclusion increases average performance, and (iii) excluded
persons adjust their beliefs about their own ability downwards hence exert lower effort.
We test these predictions using a laboratory experiment. The experimental results will
inform us whether social exclusion indeed lowers performance and the mechanisms
behind it.
External Link(s)
Registration Citation
Dogan, Gonul. 2019. "Social exclusion." AEA RCT Registry. July 24. https://doi.org/10.1257/rct.4470-1.0.
Former Citation
Dogan, Gonul. 2019. "Social exclusion." AEA RCT Registry. July 24. http://www.socialscienceregistry.org/trials/4470/history/50544.
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Experimental Details
The experiment consist of four treatments: Baseline, Performance, Color and Feedback. In Baseline, participants repeatedly solve real effort tasks. In Performance, some participants are excluded from a team based on their performance. In Color, the exclusion is due to a random assignment of color. In the Feedback treatment, participants learn the same information as in Performance with respect to their relative ranking but there is no exclusion possibility.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Within a treatment: performance difference within different types of participants (excluded vs. included in Performance and Color, and message receivers vs others in Feedback) in a given round, and performance difference of the same type of player across different
Across treatments: performance in a given round; performance difference between different types of participants in the final round.
Primary Outcomes (explanation)
Performance: the number of correct answers given by a player in a given round of a real effort task.
Secondary Outcomes
Secondary Outcomes (end points)
Within a treatment: difference in the number of attempts, error rate, and beliefs about their own performance within different types of participants across different rounds. Across treatments: In a given round, the number of attempts, error rate, and beliefs about own performance. In the final round, the number of attempts, error rate, and beliefs about own performance across different types of participants. The questionnaire at the end of the experiment includes the following: (1) Whether participants think the outcome of Task 3 is fair, (2) An open question on what they think the experiment is about, (3) Their estimate of how performance of the excluded or message receiving players changes after they learn that they have been excluded or received a message, (4) Gender, major, ethnicity, and personality traits, (5) whether participants have ever experienced social exclusion in real life and how they coped with it.
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The experiment consists of 8 rounds of real-effort task and two rounds of group discussion. The experiment is organised in blocks; in Block 1, the real effort task is repeated thrice. In Block 2, players are allocated into groups of four and engage in a group discussion. Then the real effort task is repeated thrice. In Block 3, players are first informed of the possibility of social exclusion if exclusion treatments (Color or Performance) or of the possibility of learning whether they are the worst performer (Feedback). Then, they first perform the real effort task, then engage in a group activity (excluded persons cannot), and engage in the real effort task again.
Experimental Design Details
Randomization Method
computer randomization
Randomization Unit
Groups are formed according to subjects' initial performance (non-random), player roles are randomly assigned in each group. Treatments are distributed across the sessions, also non-randomly to have a balanced set.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
In Baseline, there are no clusters. In other treatments, data is clustered at the group level even though performance remains strictly independent of others. In baseline, the aim is to get at least 50 observations, and in other treatments, about 30. This results in a total of 170 clusters.
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
50-30-30-30 for Baseline-Color-Performance-Feedback treatments
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
When comparing the performance difference between included and excluded players in last round of real-effort task in the Color treatment to that of the Performance treatment, we will use a two-tailed multiple linear regression (t-test, single regression coefficient). With α = 0.05, power = 0.80, total sample size = 28 (the Color treatment) + 28 (the Performance treatment), and the number of predictors = 3, the minimum effect size Cohen's f^2 is 0.1455200. A similar analysis holds when comparing the Feedback treatment to Performance. Finally, we will pool all the data and compare Baseline performance to the treatments when controlling for social exclusion. Then, in a multiple regression with 3 predictors (treatment, exclusion, previous round performance), and 140 observations (50 from Baseline, and 30 each from the other three treatments), minimum detectable effect is 0.0568657.
IRB Name
German Association for Experimental Economic Research
IRB Approval Date
IRB Approval Number
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)