The purpose of the audit trail is to ensure that all data transformations are exactly documented. In PMOD, the audit trail can be recorded in files or in a database. With file-based recording, the system maintains a separate audit trail text file for each PMOD user, which resides on the server machine so as to prevent unauthorized access. Additionally, there is an audit trail text file for system actions. With database recording of the audit trails, all information resides in a single database which supports flexible filtering and data export. We strongly recommend using a database for the audit trail. File based audit trails should only be used in small test environments.
FDA Publication: Part 11, Electronic Records; Electronic Signatures — Scope and Application. Aug. 2003. http://www.cfsan.fda.gov/~dms/guidance.html.