Discovery and scoping. The team inventories the source environment — every interface, every custom report, every workflow, every integrated third-party system. This phase typically surfaces dozens of integrations that no single person in the organization fully understood.
Data assessment and cleansing. The source data is profiled — measuring completeness, accuracy, duplication, and conformance to standard vocabularies. Most legacy EHRs accumulate years of data quality issues that become visible only when migration forces a reckoning. Patient duplicates, mismatched SNOMED CT codes, free-text where structured data should be, and inactive records mixed with active ones all need to be addressed.
Migration design. The team makes a series of consequential decisions: how much historical data moves into the new EHR versus stays in an archive, which data domains migrate as discrete records versus as PDF document references, how patient matching is handled, and how clinical content (order sets, clinical decision support rules, documentation templates) is recreated in the target system.
Mapping and transformation. Source data structures are mapped to target structures — patient demographics, encounters, problems, allergies, medications, immunizations, results, documents, and orders. Vocabulary translation is unavoidable: legacy local codes mapped to ICD-10, RxNorm, LOINC, and SNOMED CT. Modern migrations often stage data through FHIR resources or HL7 v2 messages so the pipeline can be tested and reused.
Build and configuration. The target EHR is configured to support the organization’s workflows — security roles, departments, locations, order catalogs, charge masters, documentation templates, and integration interfaces.
Integration reconnection. Every external system that talked to the source EHR — lab, imaging, pharmacy, billing, HIE, registries, patient portals, telehealth — needs to be reconnected to the target. This is usually the second-largest body of work after the data migration itself.
Testing and validation. Multiple cycles of mock conversions, integration testing, end-to-end clinical scenario testing, and parallel testing where the same patient is processed through both systems and outcomes compared.
Cutover and go-live. A planned transition window where the source EHR is frozen, final data deltas are migrated, and the target EHR becomes the system of record. Most large migrations include a “command center” model with dedicated support resources for several weeks post-go-live.
Stabilization and optimization. The first 90–180 days are spent triaging issues, refining workflows, and resolving data discrepancies. Optimization extends well beyond that — most organizations are still tuning their new EHR two years after go-live.