Great question, neb2.

I’ve been a part of an internal audit once before and the main advantage that I saw as a result was that it introduced to everyone what an external audit would be like and it trained multiple employees on how to handle audit questions and answers. As Dr. Simon said in the lecture, external audits can carry on for quite some time, even days. Employees need to be trained on how to answer questions when asked about a topic, and where to quickly find the documentation that the auditor asks for. Someone needs to be responsible for being a “runner” to retrieve the proper documents; someone is a secretary, and sometimes even a back up secretary; someone in charge to act as a liaison, etc. The time to learn these responsibilities is not when the FDA officer walks through the door and an internal audit is useful for that. Additionally, it gives your company a chance to catch major problems before a governmental authority does.
The only disadvantage that I have seen with internal audits, as Dr. Simon mentioned, is bias or unwillingness to speak up about a problem prior to the audit. For example, if QA is conducting the audit and they notice problems prior to the internal audit but do not voice them until the audit, it can create tension among coworkers. Concerning bias, QA can overlook something that they previously misconducted and either do not want to get themselves in trouble or honestly believe that it was not a mistake the first time but continue to miss the same issue a second time. Overall, an internal audit can help to catch minor problems before they become major ones or they can save you a bigger problem when conducting an external audit with the FDA later.