Data collection
The number of families who were offered the intervention, and families that accepted, was recorded (acceptance rate). In addition, the number of children and adolescents completing the intervention (completion rate), and children, adolescents and parents reporting their experiences with the intervention, was recorded (measure completion rate). We used both child/adolescent- and parent-reported experience measures. The children/adolescents completed a patient-rated experience measure of the interpersonal quality of healthcare encounters immediately after the intervention. The parents completed two questionnaires: one directly before the intervention, and one immediately after the intervention.