Linking routinely collected social work, education and health data to enable monitoring of the health and health care of school-aged children in state care ('looked after children') in Scotland: a national demonstration project.

BACKGROUND AND OBJECTIVES: Children in state care ('looked after children') have poorer health than children who are not looked after. Recent developments in Scotland and elsewhere have aimed to improve services and outcomes for looked after children. Routine monitoring of the health outcomes of looked after children compared to those of their non-looked after peers is currently lacking. Developing capacity for comparative monitoring of population-based outcomes based on linkage of routinely collected administrative data has been identified as a priority. To our knowledge there are no existing population-based data linkage studies providing data on the health of looked after and non-looked after children at national level. Smaller scale studies that are available generally provide very limited information on linkage methods and hence do not allow scrutiny of bias that may be introduced through the linkage process.

STUDY DESIGN AND METHODS: National demonstration project testing the feasibility of linking routinely collected looked after children, education and health data.

PARTICIPANTS: All children in publicly funded school in Scotland in 2011/12.

RESULTS: Linkage between looked after children data and the national pupil census classified 10,009 (1.5%) and 1757 (0.3%) of 670,952 children as, respectively, currently and previously looked after. Recording of the unique pupil identifier (Scottish Candidate Number, SCN) on looked after children returns is incomplete, with 66% of looked after records for 2011/12 for children of possible school age containing a valid SCN. This will have resulted in some under-ascertainment of currently and, particularly, previously looked after children within the general pupil population. Further linkage of the pupil census to the National Health Service Scotland master patient index demonstrated that a safe link to the child's unique health service (Community Health Index) number could be obtained for a very high proportion of children in each group (94%, 95% and 95% of children classified as currently, previously, and non-looked after, respectively). In general, linkage rates were higher for older children and those living in more affluent areas. Within the looked after group, linkage rates were highest for children with the fewest placements and for those in permanent fostering.

CONCLUSIONS: This novel data linkage demonstrates the feasibility of monitoring population-based health outcomes of school-aged looked after and non-looked after children using linked routine administrative data. Improved recording of the unique pupil identifier number on looked after data returns would be beneficial. Extending the range of personal identifiers on looked after children returns would enable linkage to health data for looked after children who are not in publicly funded schooling (i.e. those who are preschool or postschool, home schooled or in independent schooling).