Expert consensus in the development of a European health-related quality of life measure for children and adolescents: a Delphi study

Aim: To determine the level of consensus among experts regarding content, structure and sources of content for a new European measure of health-related quality of life in children and adolescents. Methods: A three-round Delphi questionnaire was sent by e-mail to 24 experts in quality of life measurement in 9 European countries. Consensus was considered reached when >90% of experts either agreed or disagreed with a given statement, or where median scores were over 6 on a scale of 1-10, and score dispersion was within predefined limits. Results: Completed questionnaires were received from 20 panellists in each round. It was agreed that the new instrument should be a multidimensional, profile measure with 30-49 items covering 5-8 dimensions, which should take no more than 10-15 min to complete. Agreement was also reached on 8 specific dimensions to include in the questionnaire (psychological well-being, self-esteem, body image, cognitive functioning, mobility, energy/vitality, social relations, family/home function). Consensus was against the use of individualized questionnaires. Focus groups with children, parents and workers in the field, literature and instrument reviews were considered appropriate sources for content. Conclusion: Using a Delphi method in this way for the first time showed it to be a feasible and useful method for establishing a conceptual and operational framework for the Kidscreen questionnaire.