Glossary

Data

Term	Definition
Children’s social care (CSC) data	Children’s social care provides a range of services for children in need and children at risk of abuse or neglect. The children’s social care datasets are the child in need census and children looked after return.
ECHILD	Education and Child Health Insights from Linked Data, a project that links the National Pupil Database (along with its social care data), the Hospital Episode Statistics and other NHS datasets for 20 million people born since September 1984.
Hospital Episode Statistics (HES)	All-of-England hospital admission, outpatient and emergency department data.
National Pupil Database (NPD)	All-of-England data covering children enrolled in state schools.
Pupil Matching Reference (PMR)	The unique, encrypted child identifier available in the NPD.
Token person ID (TPID)	The unique, encrypted child identifier available in HES and other NHS datasets.

Term	Definition
Academic year	The school year typically begins in September, with summer holidays starting late July. In ECHILD, we generally define an academic year as 1st September to 31st August. The NPD is organised by academic year ending, such that a table labelled 2015, for example, refers to the 2014/15 academic year.
Financial year	Strictly speaking, the financial year runs from 6th April of one year to 5th April of the next. However, the HES “financial year” runs from 1st April to 31st March. We therefore also usually define our “financial year” as running from 1st April to 31st March. HES data are organised according to financial year starting. Therefore, a HES table labelled 2018 refers to the 2018/19 year.
HES birth cohort	A cohort study whose key feature is that children are included by virture of their having a birth record in HES inpatients data. Around 98% of births in England are in NHS hospitals.
NPD inception cohort	A cohort study whose key feature is that children are included by virture of their enrolment in a state school and recorded in the NPD. Each year, around 93% of school-aged children are enrolled in state schools in England. Greater than 97% of children will ever attend state school.
Phenotype	Anything observable about a unit of study. In the context of ECHILD, and especially of HES, we are often referring to health conditions. Refer to the ECHILD Phenotype Code List Repository for more information.

Term	Definition
Key Stage	Stages of education as defined in the National Curriculum. Key Stages 1 and 2 cover primary education and Key Stages 3 and 4, secondary. School in England is compulsory from age 5 (with many children starting reception year aged 4) until the child’s 16th birthday. Those aged 16 and 17 must be in some form of education or training until they achieve a certain level of qualifications.
GCSE	General Certificate of Secondary Education. State exams sat at the end of Key Stage 4.