Co-producing a new scale with young people aged 10 – 24 years: A protocol for the development and validation of the Youth Loneliness Scale (YLS)

Background: Around half of young people aged 10-24 years in the United Kingdom report feeling lonely “often” or “some of the time”, with similar rates in other countries. These experiences of loneliness are linked to well-being and a wide range of adverse physical and mental health outcomes. However, our understanding of the aetiology and sequelae of youth loneliness, as well as the development of preventative measures and interventions, has been hampered by a lack of scales that can accurately capture the authentic experiences of young people.Methods: Here, we provide a protocol for developing and validating an age-sensitive loneliness scale for young people aged 10-24 years: the Youth Loneliness Scale (YLS). The scale will be designed to measure loneliness in the general population of young people in the United Kingdom. The scale development process will follow a multi-step approach, going from item generation to psychometric evaluation. Item generation will include a combination of verbal and non-verbal techniques to enable broad expression of what it means to be lonely as a young person. The scale has been and will be co-produced with young people from design to dissemination.Discussion: The protocol provided here allows researchers to evaluate the final scale generated against the plans set out here. We also encourage the use and adaptation of the protocol to develop age-sensitive loneliness scales in other cultural contexts and for other populations.