In what situation would the PatientKey not be a reliable identifier?

The PatientKey may not be a reliable identifier in scenarios involving snapshots. Snapshots often reflect a patient's data at a particular moment in time, capturing the state of the patient or their information during that period. In this context, if a snapshot is used to represent patient data, and there are multiple snapshots taken over different time periods, the PatientKey may lead to confusion or misalignment between what is captured in each snapshot and how that information is relevant to the overall patient journey.

For instance, if data from different time periods is analyzed collectively using the PatientKey, discrepancies may arise as patient health records can change significantly over time. Therefore, when relying on historical snapshots, the PatientKey might not be a sufficient stand-alone identifier because it would not account for variations or data shifts that occur after each snapshot is created. This limitation renders the PatientKey less reliable when considering the dynamic nature of a patient's health history within a snapshot framework.