A multi-informant, multi-method study into the mental health and well-being of Dutch children and adolescents: Ieder Kind Is Anders

This paper describes the rationale and design of the Every Child Is Different project (Dutch: Ieder Kind is Anders, IKIA). IKIA is a national crowdsourcing study designed to examine the dynamic and dimensional nature of Dutch children's and adolescents' mental health and well-being using both self-report (8-18 years) and parental report (of youth 4-18 years). Emotional processes are integral to the project as they underlie most of the processes related to mental health and well-being. Via an internet platform participants complete cross-sectional questionnaires on emotional and psychosocial development, well-being, mental health, parenting, and social environment. Participants receive automated feedback which consists of visual displays of their (sub)scores compared to the sample's average and an explanation of the subject. Participants can additionally participate in a 30-day smartphone-based diary study about their daily activities, behaviors, and emotions. This paper describes the methods and techniques used in the IKIA project, as well as future research that can be conducted with the resulting data.