The Causal Impact of an Anti-bullying Intervention on Children’s Development

Last registered on January 30, 2023


Trial Information

General Information

The Causal Impact of an Anti-bullying Intervention on Children’s Development
Initial registration date
January 27, 2023

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
January 30, 2023, 5:54 AM EST

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



Primary Investigator

University of Zurich

Other Primary Investigator(s)

PI Affiliation
Lund University
PI Affiliation

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
In this project, we study the impact of an anti-bullying randomized intervention at schools on child development.
KiVa is a large-scale anti-bullying program implemented in Finnish compulsory schools in 2007-2009. We use the original KiVa RCT data to evaluate the program's impact on children's immediate outcomes. In addition, we will link this survey data from the randomized intervention to administrative population records to examine the causal effect of the program on children's health, education, and labor market outcomes as young adults.
External Link(s)

Registration Citation

Costa-Ramon, Ana, Ana Rodríguez-González and Ursina Schaede. 2023. "The Causal Impact of an Anti-bullying Intervention on Children’s Development." AEA RCT Registry. January 30.
Experimental Details


The KiVa program was launched as a collaboration between the Finnish Ministry of Education and Culture and the University of Turku.

The KiVa anti-bullying program is predicated on the idea that the way peer bystanders react when witnessing bullying is crucial for putting an end to (or sustaining) it. Influencing the peer context is therefore an essential part of the KiVa program. The program is an intensive intervention that includes both universal (targeted at all students) and indicated actions (implemented when a case of bullying comes to attention). The universal actions consist of student lessons and a virtual learning environment (an anti-bullying computer game for primary school students and an Internet forum ‘‘KiVa Street’’ for secondary school students). The student lessons include discussion, video films, and
exercises done in dyads and small groups. The topics cover various issues related to group interaction and group pressure, the mechanisms and consequences of bullying, different forms of bullying, and especially, what the students can do together to counteract bullying and support the victimized peers. The virtual learning environments are closely connected to the topics of the lessons and themes, motivating students and enhancing their learning process. In addition, the universal actions include a parents’ guide as well as symbols (posters, highly visible vests for teachers supervising recess time), reminding both students and school personnel of the topic.

The indicated interventions involve discussions with victims and bullies, as well as with selected prosocial classmates who are challenged to support the victimized classmate. The discussions with the bullies and victims are ran by the so-called KiVa teams within the schools, whereas the classroom teacher organizes a separate meeting with the potential supporters of the victim.

Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
From the KiVa survey data, we focus on three dimensions: bullying, victimization, and mental health.
From the administrative data, we are interested in studying the following dimensions: mental health, physical health, crime, education, and labor market outcomes.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Application behavior after compulsory schooling, siblings' health and educational attainment, and parental health, marriage stability, and labor market outcomes.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design

The RCT KiVa anti-bullying program was implemented for two consecutive school years: in 2007–08, for grades 4–6 (primary school, children aged 10–12) and in 2008–09, for grades 1–3 (primary school, children aged 7–9) and 7–9 (secondary school, students aged 13–15).

The randomization was stratified at the province and school-language level (Finnish or Swedish).
Experimental Design Details
Randomization Method
Randomization done in office by a computer
Randomization Unit
Randomization was done at the school level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
In the first wave, 77 schools in Finland participated in the program. We refer to this as RCT1.

In the second wave, a total of 147 schools in Finland participated, with 74 in grades 1 to 3 (which we refer to as RCT2) and 74 schools in grades 7-9, respectively (RCT3).
Sample size: planned number of observations
Approximately 25000 individuals
Sample size (or number of clusters) by treatment arms
RCT1 (grades 4-6): 38 schools in the control group and 39 in the treatment.
RCT2 (grades1-3): 36 schools in the control group and 38 in the treatment.
RCT3 (grades 7-9): 35 schools in the control group and 39 in the treatment
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
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