# OpenHDI (Open Health Data Impact)

> A free, source-backed record of how UK health data is shared and reused for research, and what came of it. Every record keeps its source, original identifier and capture time, and every statement is labelled by how strongly it is evidenced.

How to read OpenHDI:
- An agreement permits access; a release is data actually sent; a paper that mentions a data resource has not necessarily used it.
- Benefits statements are the applicants' own words, not verified. No impact has yet been independently verified.
- "Identifier matched" links (a paper citing an NHS England agreement reference) await human review; "human verified" links have been checked by a named reviewer.
- A missing record is a coverage limitation, not evidence of wrongdoing.

## Pages
- [Data resources](https://openhdi.com/resources): UK health-data resources with custodian facts, agreements and papers
- [Data-sharing agreements](https://openhdi.com/data-uses): NHS England agreements, datasets, commercial marker and releases
- [Benefits reported](https://openhdi.com/benefits): applicant-reported benefits, not verified
- [Evidence journeys](https://openhdi.com/journeys): agreement → research → claimed impact, each link with its evidence and where it stops
- [Impact claims](https://openhdi.com/impact-claims): REF 2021 impact case studies involving UK health data, as the universities reported them
- [Publications](https://openhdi.com/publications): papers mentioning UK health-data resources (Europe PMC)
- [Registered studies](https://openhdi.com/projects): ClinicalTrials.gov and UK Statistics Authority accredited projects
- [Evidence coverage](https://openhdi.com/evidence): how far agreement-to-paper links have been traced
- [Organisations](https://openhdi.com/organisations): organisations named by the sources
- [Sources](https://openhdi.com/sources): every source assessed, its licence and limitations
- [Methodology](https://openhdi.com/methodology): evidence labels and principles

## Data
- [Public API](https://openhdi.com/api/v1/records): JSON; filter by kind, q, resource, organisationId, dataset, commercial, has
- [OpenAPI description](https://openhdi.com/api/openapi.yaml)
- [Summary figures](https://openhdi.com/api/v1/summary)
- [Sitemap](https://openhdi.com/sitemap.xml): every record page

## Data resources
- [OpenSAFELY](https://openhdi.com/resources/opensafely): A secure research environment for analysing GP records in England where they are held, inside the TPP and Optum data centres, without moving the data.
- [UK Biobank](https://openhdi.com/resources/uk-biobank): Health information, physical measures and samples from about 500,000 adults aged 40 to 69, assessed at 22 centres in England, Scotland and Wales and followed through their health records.
- [CPRD](https://openhdi.com/resources/cprd): Anonymised, coded GP records from a network of over 2,400 GP practices across the UK, which can be linked to hospital and cancer registry data.
- [SAIL Databank](https://openhdi.com/resources/sail-databank): Billions of anonymised, linkable person-based records for research, funded by Health and Care Research Wales.
- [Hospital Episode Statistics](https://openhdi.com/resources/hospital-episode-statistics): Details of admissions, outpatient appointments and historical A&E attendances at NHS hospitals in England.
- [Genomics England](https://openhdi.com/resources/genomics-england): Whole genomes from the 100,000 Genomes Project: 100,000 genomes from around 85,000 NHS patients affected by rare disease or cancer.
- [Natsal](https://openhdi.com/resources/natsal): The National Survey of Sexual Attitudes and Lifestyles, among the largest and most detailed scientific studies of sexual behaviour in the world, in waves Natsal-1 to Natsal-4 and Natsal-COVID. Funded by Wellcome, with ESRC and NIHR contributions.
- [ONS Secure Research Service and death registrations](https://openhdi.com/resources/ons): The Secure Research Service gives accredited researchers secure access to de-identified, unpublished ONS data under the Five Safes framework. NHS England also shares registered deaths in England and Wales since 1993, as provided by ONS.