Accepted: 22 February 2021
First Online: 7 April 2021
: KRK was involved in the development of the ICHOM standard set of outcomes for child and youth anxiety and depression and received personal fees from ICHOM during the development of the set (October 2018-March 2020). The ICHOM standard set is available free of charge and there is no financial conflict of interest. KRK is involved in the development of a core outcome set for adolescent depression clinical trials as part of the International Network for Research Outcomes in Adolescent Depression Studies (IN-ROADS) initiative. JEC and MW were involved in the programme of service transformation that generated the data that this manuscript draws on. MW led the outcomes and evaluation group that agreed the approach to measurement used in the initiative. MW is now Head of the new Mental Health Priority Area at the Wellcome Trust, which may be developing core outcome sets in mental health in the future. MW has been involved in the development of the Current View Tool, which is a freely available measure and there is no financial conflict of interest. MW was previously Head of the Child Outcomes Research Consortium (CORC), which advises on measurement in child mental health, and she was an advisor to NHS England on informatics. RS has no conflicts to disclose.