This data flow diagram illustrates how childhood immunization information is exchanged across providers and federally qualified health centers, electronic health records, health plans, the California Immunization Registry, health information exchanges and qualified health information organizations, public health authorities, claims databases, and HEDIS data aggregators. It also shows how these data connections support quality measurement, provider payment, and access to more complete patient immunization records. Practices and partners can use the diagram to understand the current data ecosystem, identify potential gaps or duplication, and support discussions about improving record accuracy, interoperability, and immunization measure reporting.