When discussing the European Health Data Space, the focus is often placed on data itself – how it is shared, governed, and used. However, during Understanding Patient Data's EHDS Unpacked webinar, Zuzana Nordeng, Senior Adviser and Metadata Manager at the Norwegian Institute of Public Health, emphasised that the true starting point is metadata – the map that enables us to navigate it.
Seeing what already exists
In Norway, we are fortunate to have large volumes of high-quality health data. Our registries follow people across their lives, from birth through to chronic disease and beyond. But for many years fragmentation meant that this data was difficult to find and even harder to understand from the outside.
Metadata is what allows us to move from fragmentation to visibility. It is how we make health data findable, accessible, interoperable and reusable. Without this, even the best datasets remain effectively invisible.
Building the national map
Our approach in Norway has been to build a national metadata ecosystem – not all at once, but step by step.
This has included:
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Developing a national metadata specification, so that all registries describe their datasets in a consistent way
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Creating a health data portal, where users can explore what data exists and how to access it
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Building a national metadata management system, a repository that brings together metadata from across the system
These components together form a map of our health data landscape – one that can be used by researchers, policymakers, and others before they even begin a data application.
Designing for the user journey
One of the most important lessons we have learned is that metadata changes the experience of using data. Without metadata, the process begins with uncertainty – you apply for data without fully knowing what exists. With metadata, the journey is different – users can explore data sources with data collections, browse variables in the variable explorer, create variable lists, understand context and quality, and then make informed decisions about what to request.
This may sound like a small change, but it has a large impact. Applications are better, processes are faster, and the system becomes more efficient overall. In this sense, metadata is just as much a service to the user as it is a technical layer.
Incentives and collaboration
Building this map has not been simple. We have had to bring together many different data holders, each with their own systems and priorities. To support this, incentives were important – encouraging registries to provide metadata and prioritise quality improvements.
But beyond incentives, collaboration has been essential. Metadata is not something that can be created centrally and forgotten. It requires ongoing contribution, governance, and shared responsibility.
Metadata as infrastructure
For the European Health Data Space (EHDS), I believe the key lesson from Norway is that metadata is infrastructure rather than simply an add-on.
The EHDS depends on making health data discoverable and usable across borders, and this requires consistent, shared approaches to describing and cataloguing information. National metadata systems, like those developed in Norway, form the essential building blocks of this wider European ecosystem. They create a common language for data, support interoperability, and enable users to navigate complex data landscapes with confidence – turning ambition into something that can work in practice.
A map for trust
Metadata lends to data usage factors beyond just technical standards. By clearly describing data – its purpose, its quality, its legal basis – we make the system more transparent. And transparency is what enables trust, whether for researchers, policymakers, or the public.
In Norway, we have learned that building a health data system is not just about connecting datasets, but rather ensuring they are visible and understandable, as only then can we truly navigate them.
Find out more about Understanding Patient Data's engagement with the European Health Data Space, and catch up on EHDS Unpacked Part Two: Global lessons for building a trusted health data space.