All information in the EKG, and associated artifacts, are linked to defined and prioritized use cases. Nothing in the EKG exists without a known business justification and purpose.
An EKG use case encompasses a business narrative and outcome with a clear description as to which exact business capability is supported, expressed in business terms and links to relevant data stories, personas, business concepts, ontologies, vocabularies, taxonomies, datasets, workflows, user experience models, life-cycle model, deployment model, backlog, test scenarios, quality metrics, benchmark metrics, success definitions, performance indicators and other details.
Importantly, the use cases for an EKG can make use of lower level use cases, thus forming a so-called use case tree, though it is not a strict hierarchy since common use cases can be reusable. At an implementation level a use case may be associated with "user stories" or "data stories" that form the points of interaction with end users or client systems. The vision is that a fully fleshed out and implemented use case can be deployed as a reusable component.
Use cases anchor the EKG to real business needs, and allow it to evolve incrementally while delivering business value. Without this, the tendency is often to focus on information modeling for its own sake, without a focus or rationale for what to include or exclude. The use cases provide the basis for associating users with EKG functionality and provide the context for information selection.
The use cases themselves need to be developed and managed as part of the EKG development method, and ideally as part of the EKG itself.