EPR programmes succeed or fail on one thing: how well legacy data is consolidated, structured, and trusted. Bringing together data from multiple legacy systems into a single, longitudinal patient record is rarely straightforward, differences in formats, coding standards, and data quality can quickly undermine usability. Without careful standardisation and validation, critical clinical context can be lost, reducing clinician confidence and adoption. Ultimately, if the migrated data isn’t accurate, accessible, and trusted from day one, even the most advanced EPR platform will struggle to deliver its intended clinical and operational benefits.