What is an informal QRM method?

The term "formality" or "informality" should not be confused in this context with the basic requirement for documentation within the framework of good manufacturing practice. Rather, it means that methods and tools can also be applied which are not described in the literature or the internal procedures of a company or an organisation and which do not necessarily have to have a formal procedure or a defined scope.

[GMP Compliance Adviser, Chapter 19.D]