All intervention groups (O, T and RT) received standardised practical CPR training and the participants used an individual training manikin, MiniAnne (manufactured by Laerdal, Stavanger,Norway), during training. The training sessions were conducted in accordance with current European Resuscitation Council guidelines.20 (link) Training was performed in a whole-class set-up with 14–29 students in each class. Teachers at the schools, who all were CPR instructors, were responsible for the CPR training.6 9 18 (link) They received oral and written information to be updated on the present interventions. CPR training was carried out during a 45–60 min lesson. The training was either mobile application or digital video disc based,21 (link) evenly distributed in the intervention groups (table 1). The teachers served as facilitators of the CPR training sessions as previously described.21 (link) After the standardised practical CPR training, the additional interventions, test and reflection, were performed.