Why addresses matter: powering better health decisions

The power of place and accurate location data is also why GEO Business is such an important event for Ordnance Survey (OS). As the UK’s largest geospatial event, it brings together people involved in the capture, analysis, and use of geospatial data, showing how location intelligence can support smarter decision-making across industries.

At this year’s event, OS joined NHS England to explore a simple but powerful idea: how better addressing data can support better health decisions.

The session, “Why Addresses Matter: Powering Better Health Decisions,” was presented by James Lockyer, Lead Data Engineer at NHS England, and myself.

Addresses in health infrastructure

For OS, addresses are an integral part of a wider, national, geospatial foundation. Through the Public Sector Geospatial Agreement (PSGA), OS creates, maintains and improves the National Geographic Database (NGD), which includes more than 40 million addresses, 500 million location features, and around 20,000 updates every day.

Now we compare that with the NHS’s addressing systems: NHS England holds more than 110 million discrete addresses for England alone, which is more than three times the number of residential properties in the UK.

This occurs due to differences in capitalisation, spelling, errors, and formatting. Some patients have more than 40 address transactions in a single day, with more than 500 million address transactions stored across 80 million patient records.

Many challenges come from legacy systems and historic data-entry practices. Some systems have short input field lengths that cause truncation, and address data may sit across five fields without a fixed structure, meaning content can appear in different positions. Free-text input can also contain information that is not part of the address at all, such as telephone numbers or door access codes.

And NHS England isn’t allowed to correct the errors in its data. The result is duplication, inconsistency, and ambiguity. In a health context, these addressing inconsistencies can have serious implications.

Because a patient’s address is the link between the person and their geography. Where a patient lives, what services they may be able to access in the surrounding area – accurate addressing helps connect individuals to where services are delivered, how risks are understood, communities are planned, and public health decisions are made.

Supporting the NHS 10-Year Plan

Fortunately, there is the NHS 10-Year Plan, which includes several priorities that are intrinsically place-based:

• Improving health inequalities
• Strengthening population health management
• Developing preventative healthcare
• Integrating and localising care
• Supporting healthcare neighbourhoods
• Designing services around patients and users

An NHS “… that predicts and prevents ill health rather than simply diagnosing and treating it.”

These priorities depend on a clear understanding of people and place; it depends on data infrastructure that links patients, services, demographics, and geography in a consistent and trusted way.

NHS England’s work aims to move beyond fragmented addressing towards centralised, consistent resources that support both operational and analytical use. The goal is to reduce duplication, link spatial and non-spatial data more effectively, and ensure a single source of trusted reference data.

Creating a foundation for better decisions

NHS England’s approach to developing its geo-infrastructure includes several key components: a geo-repository of boundary and point data, a daily updated list of service locations, a postcode index, an address index, and a person index.

The Address Index is a core element. Derived from OS NGD Address data, it is intended to provide a centralised resource for addresses and related data.

Integrating UPRNs

Within this Address Index, NHS England uses the Unique Property Reference Number (UPRN) – a unique, numeric identifier for every addressable location in Great Britain. It applies to residential and commercial buildings, and to objects that may not have a conventional postal address, such as a bus shelter. A UPRN is persistent and never reused, staying with a property throughout its lifecycle.

It’s a layer of addressing beneath the postcode: a block of flats, for instance, may have one postcode, but each flat within that block has its own UPRN.

In addition to UPRN linkage, the Address Index can support address capture at the point of input, daily updates, and connections to wider geo-demographic datasets, including geographic boundaries, Energy Performance Certificate data, CACI Acorn data, and changing NHS commissioner and provider geographies.

This wide integration of data enables the NHS to better understand patients, and improve their services.

Data linkage to real-world impact

One practical example is the development of a care home flag. By combining OS NGD Address data, OS Sites, OS Buildings and Care Quality Commission data, NHS England has created a single list of care homes over time.

This has become an accepted model for identifying patients who reside in a care home. It has supported vaccination programmes by helping ensure patients are vaccinated, and has been shared with UKHSA and Integrated Care Boards to support their work.

Place-based insight starts with trusted foundations

Better health decisions depend on trusted, connected data. Addresses and UPRNs provide a way to link people, services, and places together, consistently, helping the NHS understand need, plan care, and respond to changing circumstances.

For OS, we know where geospatial data can make a difference. Authoritative and accurate addressing creates the common reference points that allow complex systems to work together.

In the healthcare sector, those reference points can support fairer access, better planning, more preventative models of care – to help make critical decisions for smarter outcomes, and ultimately, better care.