I thing the biggest advantage for internal audit, it gives you a chance to verify that your CAPA have been completed effectively and on time or not!. Also, the ability to identify non-compliance thing in the product and provide recommendations on ways to make improvements. Look at internal auditing not only as a regulatory compliance check, but as a necessary means to continuously improve the efficiency of GMP and product quality.

An effective internal auditing takes a progressive, forward-looking mindset that helps people point out problems before they arise. By doing an audit, a company can understand how activities and processes are operating and always looking for ways to improve it. It also allows to dwell into know problem areas and develop an action plan to make corrections and improvements. It can also help identify a company's most critical areas and that everything must be in place for it to keep functioning flawlessly.

There is a big advantage of besides being prepared. As an employee involved in improving and auditing the company's procedures, there is a double insight that can help the audit in seeing if the improvements are actually viable. Another is catching mistakes on information that could lead to a snowballing effect if done by the FDA or 3rd party. This can help cut the problem before it leads to issues. It helps the employee stay up to date on the regulations because audits should be down with the most up to date guidelines. The biggest disadvantage is that because it ones in the workplace, there can always be something missed. If there is not enough manpower to do a proper internal audit, then the employee might end up checking his/her own work. It is always a good practice to have internal audit so the company is prepared, but having regular 3rd party audits will so improve practices and hopefully lead to a prepared and proper company for the FDA to audit.

To add to this discussion, I think its important to note that an internal audit does not mean that it has to be performed by the company employees. For example where I work we do our own internal quality audits where we hire an external third party to perform the audit and that is basically us auditing ourself where we can find the problem or issue. Then we can be prepared and can make any corrections we need before ISO or FDA does or they can see that we have found the issue and we are working to rectify it. This common practice not just in quality controls but with finance as well. I personally think that internal auditing is very helpful and useful way to ensure processes are working effectively and that proper documentation is in place. I think its also helpful to note that when you are working on negotiating contracts where maybe you are licensing a product, or contract service out etc you will come across language in the contract regarding auditing.