Assessment of findability within catalogues, including whether the catalogue listed target e-cohorts from table 2 (see figure 1)
| Catalogue name | Target e-cohorts listed | Searchability | Metadata | Unique and persistent identifier | |
| Found in 2018 but not in 2021 | Health Data Finder for Research | Clinical Practice Research Datalink (CPRD) Hospital Episode Statistics (HES) | Can filter | Dataset and field level | No |
| Children and young people’s health data catalogue 2009 | – | Downloadable file | Dataset level | No | |
| Found in 2018 and 2021 | NHS Digital: Data and information | HES | Search bar; Can filter | Dataset level | No |
| NHS England Data Catalogue | HES | Search bar; Can filter | Dataset and field level | No | |
| Perinatal mental health: national datasets | HES | Downloadable file | Dataset and field level | No | |
| Asthma UK Data Catalogue | HES In addition in 2021: SAIL QResearch Clinical Practice Research Datalink (CPRD) PIS | Search bar; Dropdown list | Dataset level | No | |
| Urban Big Data Centre Health and social care data | – | Dropdown list | Dataset level | No | |
| Social Services Improvement Agency Data Catalogue | – | Downloadable file | Dataset and field level | No | |
| National Data Catalogue Scotland | PIS | a-z listing | Dataset level | No | |
| Not found in 2018, found in 2021 | DataCat (University of Liverpool) | – | Search bar; Can filter | Dataset level | Yes |
| ORDA (University of Sheffield) | – | Search bar; Can filter | Dataset level | Yes | |
| UK Data Archive | – | Search bar; Can filter | Dataset level | Yes | |
| University of Lancaster | – | Search bar; Can filter | Dataset level | Yes | |
| Mauro Data Mapper/Oxford Metadata Catalogue | – | Dropdown list | Dataset and field level | Yes | |
| Zenodo | – | Search bar; Can filter | Dataset level | Yes | |
| Health Innovation Gateway | CPRD PIS SAIL HES Grampian | Search bar; Can filter; Dropdowns; Highlight new datasets | Dataset level | Yes | |
| Social Care Wales | – | Search bar; filter; show all | Dataset level | No | |
| ONS Secure Research Service | HES | Spreadsheet | Dataset level | No |
For catalogues found in 2018, these were revisited in 2021; two were inaccessible, the other eight were unchanged in terms of metadata detail and presence of identifiers.