Care proceedings are the most powerful child protection intervention; local authorities make applications for over 20,000 children each year in England and Wales. The Department for Education holds two administrative databases of children who receive services, for children looked after and children in need. These databases do not record the use of care proceedings. Data linkage is a powerful tool for revealing patterns not visible from a single data set; the Outcomes for children before and after care proceedings reform study linked these administrative records with a research database of care proceedings to examine children's care and service journeys associated with care proceedings. The researchers also devised a simplified method for use by local authorities with their own records and tested this with North Yorkshire County Council. Analysis of the linked data reveals how care proceedings are used and the impact of care proceedings on care demand. It provides the basis for analysis of cohorts of children subject to proceedings and feedback to social workers, children's guardians, and the judges and lawyers on their decisions and children's outcomes.