Integration through friendship – evidence from a peer matching program in Sweden

Last registered on August 17, 2023


Trial Information

General Information

Integration through friendship – evidence from a peer matching program in Sweden
Initial registration date
June 22, 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
June 26, 2022, 5:24 AM EDT

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

Last updated
August 17, 2023, 8:02 AM EDT

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


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Primary Investigator

Stockholm School of Economics

Other Primary Investigator(s)

PI Affiliation
Stockholm School of Economics

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
We evaluate a program that promotes social and economic integration of recent migrants to Sweden by matching them with a Swedish buddy (an established Swede) in order to create local social ties through repeated social interaction. The program is implemented in the broader Stockholm area by the Kompis Sverige (KS), a non-governmental organization partner. We use an oversubscription-based individualized lottery to select roughly 400-500 migrants (out of 800-1000) to be matched to a Swedish peer and we aim to study outcomes at 6 and 12 months. Key outcomes are: social inclusion (culturally and socially), social attitudes, especially on belongingness, measures of Swedish language ability, and current employment and education status.
External Link(s)

Registration Citation

Björkman Nyqvist, Martina and Abhijeet Singh. 2023. "Integration through friendship – evidence from a peer matching program in Sweden." AEA RCT Registry. August 17.
Sponsors & Partners

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Experimental Details


Program. The peer matching program matches Swedes and migrants based on a set of characteristics, most notably their municipality of residence, gender, age, interests and educational or professional background. The matched pair receives information about their peer through e-mail and SMS. They then schedule their first meeting. KS ensures that the peers have made contact within a week. It is up to the individuals to decide how and how often they should be in contact with each other, but KS recommends regular in-person interactions with an advisory guideline for about 6 hours per month. When interacting without supervision, the pairs typically meet for coffee, home visits, or activities like going to a concert or walking together. KS checks with participants through SMS whether their match worked well after six weeks and offers re-matching upon request.

Implementing partner. The peer-matching program under evaluation is run by a local nongovernmental organization, Kompis Sverige (KS), active in Sweden since 2013 in several cities. Since the start, KS has been working in the broader area of migrant integration in Sweden. Their activities include the program under evaluation, various workshops for schools and workplaces, and the organization of social activities and events to foster interaction between migrants and established Swedes. KS has established collaborations with several municipalities, relevant trade unions and larger businesses. In addition, their work has been covered in major national outlets, including Swedish radio and the most prominent Swedish daily newspapers.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Primary outcomes. The primary outcomes for evaluating the program's impact are (i) size and intensity of social network, (ii) social inclusion and belongingness in Swedish society, (iii) labor market outcome, and (iv) cultural assimilation. Indicators for employment and educational status, and social inclusion and sense of belonging in our surveys, are adopted from the EVS and the WVS surveys.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Furthermore, if survey risks such as partial implementation and attrition are kept under control, we plan to include two incentivized innovative measures of social ties in Sweden in our endline survey (described in PAP)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The KS team will select two migrants from the pool of migrants willing to be matched (and who have given consent to be part of the study) to each established Swede who is willing to be matched into a pair. We will randomly select one of the migrants to be the treated migrant, and the other to be a control individual. We expect to assign about 500 migrant individuals to treatment and 500 to control status.
Experimental Design Details
Not available
Randomization Method
Randomization done by computer
Randomization Unit
Individual randomization, stratified by pairs
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
500 pairs (1 treatment and 1 control individual each)
Sample size: planned number of observations
350-500 This will depend on attrition in the sample at endline.
Sample size (or number of clusters) by treatment arms
The randomization is at the individual level. We plan to have 500 pairs of individuals.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
JPAL Europe (Paris School of Economics)
IRB Approval Date
IRB Approval Number
2020 008
Analysis Plan

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