Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Many anti-bullying programs have been developed and tested for primary education. However, teachers still experience difficulties when dealing with bullying. In the current project we investigate how anti-bullying programs can better support teachers in identifying and dealing with bullying. The main aim of this studyis to examine the effectiveness of an anti-bullying intervention on elementary teachers' ability to effectively deal with bullying and children’s bullying behavior.

Who can participate?
Students and teachers in grades 3-6 in the Netherlands

What does the study involve?
The study involves the PRIMA anti-bullying program for primary schools. The study aims to compare the effects of PRIMA from the viewpoints of teachers and students. The schools were randomly allocated to one of three groups. In one group, students received the PRIMA program, including the lessons for students (PRIMA-L+). In the second group, students received the PRIMA program without this curriculum (PRIMA-L-). The third group used their 'care as usual' policy, which means that they implemented nationally established anti-bullying guidelines, such as monitoring students’ wellbeing at school, having an anti-bullying coordinator, and having a social safety policy.

What are the possible benefits and risks of participating?
Schools received PRIMA as a free trial, either immediately (for the first two groups) or following the study (for the third group). Students might benefiot from a reduction in bullying as a results of the study. Risks to students or teachers were not expected.

Where is the study run from?
The University of Amsterdam (Netherlands)

When is the study starting and how long is it expected to run for?
April 2017 to July 2018

Who is funding the study?
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands Organisation for Scientific Research)

Who is the main contact?
Marloes van Verseveld,

Trial website

Contact information



Primary contact

Ms Marloes van Verseveld


Contact details

Wibautstraat 2-4
1091 GM
+31 633401255

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

Effects of implementing multiple components in a school-wide anti-bullying program: a randomized controlled trial in elementary schools


Study hypothesis

1. Bullying and victimization decrease significantly more in PRIMA schools compared to the control schools and this effect is stronger for PRIMA schools that include a student curriculum
2. The use of more universal components is related to stronger program effects.

Ethics approval

Approved 10/04/2018, Ethics Committee of the Faculty of Social and Behavioural Sciences of the University of Amsterdam (Nieuwe Achtergracht 129B, 1018 WS Amsterdam, the Netherlands; +31 (0)20 525 6686;, ref: 2017-CDE-8008

Study design

Interventional non-blinded cluster-randomized trial

Primary study design


Secondary study design

Cluster randomised trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Prevention of bullying behavior in schools


Intervention: PRIMA, a school-wide and modular anti-bullying program for elementary school, including six core program components (i.e., student curriculum, monitor report, e-learning, face-to-face training, protocols for specific bullying situations, protocols for students involved in bullying situations). The duration of the program is different for each program component. In total, the program's duration of the universal components (i.e., student curriculum, e-learning, face-to-face training) is 12 h for each school year, excluding the time needed for reading and implementing indicated measures (i.e., protocols and monitor report).

Control: 'care as usual' (i.e., regular anti-bullying activities as required by the Social Safety at School Act in the Netherlands.

After stratification of schools by school size, the number of special needs students in the school, and the urbanization level of the location of the school, schools were randomly assigned to one of the two experimental arms or the control group. In the PRIMA-L+ condition, schools received all core components of the PRIMA program, including the student curriculum. In the PRIMA-L- condition, schools received all core components of the PRIMA, except for the student lessons. The control schools carried out a 'care as usual' policy.
School staff members and teachers implement the program in the schools. One teacher or school nurse is appointed as coordinator for the PRIMA program.

Intervention type



Drug names

Primary outcome measure

Data was collected at two time points: September/October 2017 and March/April 2018
1. Self-reported victimization measured using the global item from the revised Olweus Bully/Victim Questionnaire (OBVQ)
2. Self-reported bullying measured by eight items based on the OBVQ
3. Peer-reported victimization, students were asked to nominate students who were being bullied in the past couple of months
4. Peer-reported bullying, students were asked to nominate students who bullied other children in the past couple of months

Secondary outcome measures

Peer-reported reinforcers, outsiders, and defenders. Based on the Participant Roles Questionnaire, three single items were used to identify students’ participant roles in bullying situations concerning the past couple of months.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Schools containing more than 50 students
2. Schools that were not already using an anti-bullying prevention program
3. Schools that were not participating in any other study in this area
4. Schools that were willing to receive additional information about the study

Participant type


Age group




Target number of participants

The 31 participating schools included a total of 174 classes representing 4,285 students in grades 3-6 who were eligible for participation in the study. Active informed consent was given by parents for the participation of a total of 3,135 students (73.2% of the initial sample, Mage = 10.00, SD = 1.21). In all groups, an approximately equal percentage of students received written permission from their parents (PRIMA-L+ condition: 70.7%; PRIMA-L- condition: 79.5%; and control condition: 69.1%). The PRIMA-L+ condition comprised 873 students (Mage = 9.97, SD = 1.23), the PRIMA-L- condition had 982 students (Mage = 10.05, SD = 1.17), and the control condition contained 1,389 students (Mage = 9.98, SD = 1.21).

Total final enrolment


Participant exclusion criteria

1. Grades below third grade
2. Classes with trainee teachers

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Schools in the Netherlands

Sponsor information


University of Amsterdam

Sponsor details

Nieuwe Achtergracht 127
1018 WS
+31 (0)20 525 6050

Sponsor type




Funder type


Funder name

Nederlandse Organisatie voor Wetenschappelijk Onderzoek

Alternative name(s)

Netherlands Organisation for Scientific Research, Dutch National Scientific Foundation, Dutch National Science Foundation, NWO

Funding Body Type

government organisation

Funding Body Subtype

National government



Results and Publications

Publication and dissemination plan

A manuscript for publication in a scientific journal in 2020, and publication in Dutch professional-based journals (for teachers and school staff).

IPD sharing statement:
The datasets generated during and/or analysed during the current study will be available upon request from Marloes van Verseveld ( The data will be accessible in the autumn of 2020 for the promotion committee of the University of Amsterdam and will be available for the period of 10 years. Data in the available datasets is anonymised. Data with personal information has been stored separately on a secure server of the HvA and will be deleted after the completion of this study.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

2018 initial results presented at the European Public Health Conference in (added 08/06/2020)

Publication citations

Additional files

Editorial Notes

07/10/2020: Uploaded protocol 8 December 2014 (not peer reviewed). Uploaded statistical analysis plan. 08/06/2020: Trial's existence confirmed by the Ethics Review Board of the Faculty of Social and Behavioral Sciences, University of Amsterdam.