By adopting the 2030 Development Agenda and the Sustainable Development Goals (SDG) monitoring framework, countries are working towards improving the livelihoods and prospects for children and adolescents to ensure they reach their full potential. To this end, it is key to understand the circumstances in which they live, the barriers they face as well as which programmes and policies work for whom and under what conditions. One cannot improve what is not measured, and disaggregated data on children and adolescents by important dimensions, such as sex and gender, help to uncover how
circumstances, barriers and needs may differ by subgroups.