Metadata for clinical data sources in derivation dataset (ALHS)
| Data Source | Number of Records | Number of Individuals | Extraction Date | Data Specification Date Range |
| Primary Care Prescribing* | 4 709 231 | 47 095 | October 2018 | January 2009–April 2017 |
| Primary Care Encounters* | 11 766 100 | 49 307 | March 2018 | January 2000–November 2017 |
| Accident & Emergency | 1 831 789 | 500 321 | November 2017 | June 2007–September 2017 |
| Hospital Inpatient Admissions | 1 668 957 | 342 838 | August 2018 | January 2000–March 2017 |
| Mortality | NA | 91 758 | May 2018 | January 2000–March 2017 |
*Records available for subset of study population with asthma diagnosis only.