Attributable is part of ALCOA that tells us that it should be possible to identify the individual or computerized system that performed the recorded task. The need to document who performed the task / function, is in part to demonstrate that the function was performed by trained and qualified personnel. This applies to changes made to records as well: corrections, deletions, changes, etc.
This means that records should be signed and dated using a unique identifier that is attributable to the author. Where author means the individual who created or recorded the data.
Understanding what role the individual is playing in the task is critical. There are basically six: Executor, Preparer, Checker, Verifier, Reviewer and Approver.