Differences between the original Greater Manchester study and the two replication studies
| Original study | National analysis 1 | National analysis 2 | |
| Population | Patients registered with a GP in Greater Manchester. Does not include individuals who have opted out of secondary use of their GP data. | Patients registered with a GP in England, UK, in practices that opted in for GPES extraction. Does not include individuals who have opted out of secondary use of their GP data. | |
| Primary care data | Direct feed from GP practices. Containing all events in the patient record. | Data from the GDPPR dataset. Contains a subset of records in the patient record that were both available via GPES and considered relevant to pandemic planning and research. | |
| Admission data | Direct feed from each hospital within GM | HES APC data | |
| COVID-19 test data | From GP record | From GP record | From SGSS data and GP record |
APC, Admitted Patient Care; GDPPR, General Practice Extraction Service Data for Pandemic Planning and Research; GP, General Practice; GPES, General Practice Extraction Service; HES, Hospital Episode Statistics; SGSS, Second Generation Surveillance System.