Database Lock, Study Close-Out, and Archival
Database lock is the formal point after which the database is frozen for analysis. Prerequisites: all queries resolved or documented as unresolvable, SAE reconciliation complete, coding complete, data review/medical review signed off, protocol deviations reconciled, and the lock checklist approved by authorized signatories. After lock, changes require a formal unlock procedure with documented justification and re-lock.
Know the sequence: soft lock (data expected complete, final checks) versus hard lock (final, analysis-ready). Understand the deliverables: the locked database, the audit trail, the data management report, and the archival package. Archival must preserve data, metadata, and the audit trail in a retrievable, readable format for the required retention period (often at least two years after the last marketing approval or study termination, per applicable regulation - verify study-specific requirements).
Traps: assuming lock means the database can never change (unlocks are possible with documentation); forgetting that the audit trail must be archived with the data; treating soft lock as final; and locking before SAE reconciliation or coding is complete. Another trap: assuming archival means only the dataset - metadata, CRF specifications, and system documentation are also required.
Rule of thumb: lock is a controlled event with a checklist and sign-offs, not a date on a calendar. Worked example: one day before planned lock, a query remains open. The team does not lock; they resolve or formally document the query as unresolvable with justification, complete reconciliation, obtain sign-offs, then lock - preserving the audit trail in the archive.