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+This page is aimed at researchers working with NHS England patient record data
+as provided by the OpenSAFELY backends.
+
+## Continuity of patient data
+
+Within the NHS in England, it is usually assumed that
+a patient's current primary care record is complete:
+when a patient moves practice to another practice in England,
+their record moves with them.
+The electronic health records of patients transferring between practices in England
+should automatically get transferred via the GP2GP system.
+
+Known caveats are that:
+
+* not all data may be transferred; for example, appointment data
+* not all data may be available at once; for example, information on repeat prescriptions
+
+Refer to the [GP2GP site](https://digital.nhs.uk/services/gp2gp)
+and the [GP2GP Key Activities documentation (PDF)](https://digital.nhs.uk/binaries/content/assets/website-assets/services/gp2gp/gp2gp_key_activities_2017_v0_4.pdf)
+for further details of this transfer process.
+
+!!! note
+    Researchers using OpenSAFELY may wish to select patients
+    with a continuous registration.
+    "Continuous registration" here means that
+    a patient did not change practice during a time period of interest.
+
+    For TPP,
+    there is a [method to select patients with a continuous registration](../reference/schemas/tpp.md#practice_registrations.spanning).