Preventing the social exclusion of immigrants

Last registered on May 19, 2023


Trial Information

General Information

Preventing the social exclusion of immigrants
Initial registration date
September 06, 2021

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
September 08, 2021, 2:50 PM EDT

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

Last updated
May 19, 2023, 6:15 AM EDT

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



Primary Investigator

Harvard University

Other Primary Investigator(s)

PI Affiliation
Harvard Kennedy School
PI Affiliation
Harvard Business School
PI Affiliation
Aalto 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.
This study aims to foster social acceptance of immigrant children among native students and teachers, and to prevent social exclusion of minorities. These issues are extremely salient and relevant in the Finnish context, where 98% of teachers report that they have intervened to deal with episodes of discrimination, but only 44% of students thought that teachers’ promptly and effectively acted in response to bullying and social exclusion. We will evaluate the impact of workshops intended to reduce social exclusion run by a local NGO (Walter), implemented in a sample of 92 elementary schools in Finland over a three year period. Walter will run two types of workshops. The first one will target students directly in order to promote inter-group interactions in the classroom. The second workshop will be centered on training native teachers by sharing with them the tools to foster communication and reduce discrimination in their classroom. The common goal of the interventions is to foster social acceptance of immigrant children among native students and teachers, and prevent social exclusion. We will evaluate the effects of these workshops together and separately. To maximize power, we will first evaluate the effects of both treatments (with treatment status pooled). Next, to understand whether teacher centered workshops are substitutes for student centered workshops, we will compare the magnitudes of the effects from both treatment branches.
External Link(s)

Registration Citation

Carlana, Michela et al. 2023. "Preventing the social exclusion of immigrants." AEA RCT Registry. May 19.
Sponsors & Partners

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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Decreased discrimination and bullying, increased minority-majority friendships, and improved grades - particularly for students from immigrant backgrounds.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Implicit and explicit bias. Follow up studies will look at register-data outcomes for educational choice, grades, and school transitions. We also hope to conduct a follow up survey during middle school to measure persistent effects of bias reduction, and integrated social networks.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We are running an RCT targeting 5th grade students in 92 schools over a three year period. Each year, 3 classes in 15 schools are offered student workshops to promote multiculturalism, and all 5th grade teachers. These workshops are offered by Walter ry to the schools. In the summer of 2021, we randomized the set of schools which receive treatment; given that the number of classes in each grade in each school fluctuates from year to year, class-level randomization takes place annually.
Experimental Design Details
Randomization Method
Randomization took place on a computer. First, we ran 20,000 randomizations, checking for balance on school-level variables. Second, we kept the top 2,001 randomization vectors in terms of balance. Finally, we selected one randomization vector at random from this set for treatment. This will allow us to supplement our traditional analysis with a set of 2,000 pre-specified randomization vectors for randomization inference.
Randomization Unit
School by year, by classroom.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Roughly 270 school by year units.
Sample size: planned number of observations
Roughly 20,000 students.
Sample size (or number of clusters) by treatment arms
Over the three year period, 45 schools (by year) will be offered student centered workshops, while 60 schools (by year) will be offered teacher workshops. Another 141 schools (by year) will remain untreated.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Our power calculations suggest that the minimum detectable effect will be about 0.05 standard deviations for both native students as well as those from an immigrant background.

Institutional Review Boards (IRBs)

IRB Name
Aalto University Institutional Review Board
IRB Approval Date
IRB Approval Number
IRB Name
Harvard University IRB
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