Healthcare organisations have recently recognised patient experience as an important part of their quality care. By measuring and improving the patient experience, healthcare organisations can affect multiple parts of the care. However, children's patient experience has yet been understudied although it has been recognised that adults cannot provide as accurate views of children's experiences as children.

This thesis focused on studying how digital services can be used to measure patient experiences. A digital service was designed and developed for measuring children's patient experience. Then, the digital service was used and evaluated in a case study, where the effects of preoperative medical clowning to patient experience were studied. The patient experience was studied from three different point of views; the child patients, their parents and the nurses. The case study was conducted at HUS Children's Hospital in Helsinki. This thesis was part of the LAPSUS research project.

Based on the results of this study, a digital service can be used to measure patient experience. Children as young as 4 can report their experiences with child-friendly digital services. Findings of the case study indicate that preoperative medical clowning affects the patient experience of child patients and their parents in a really positive way. The study did not find differences in the cannula insertion procedure regarding the presence of the preoperative medical clown from the nurses' point of view.

This study provides insights on patient experience and ways to measure it with a digital service. Also, this thesis was the first study about the effects of the preoperative medical clowns to patient experience in Finland. The recommendations of the study are to support both patient experience measurement with a digital service and preoperative medical clowns more in children's hospitals.