"[1] The term actor refers to a group (consisting of one or more stakeholders or users) that requires a change in the module.
Robert C. Martin, the originator of the term, expresses the principle as, "A class should have only one reason to change".
[2] Because of confusion around the word "reason", he later clarified his meaning in a blog post titled "The Single Responsibility Principle", in which he mentioned Separation of Concerns and stated that "Another wording for the Single Responsibility Principle is: Gather together the things that change for the same reasons.
[8] In 2014 Martin published a blog post titled "The Single Responsibility Principle" with a goal to clarify what was meant by the phrase "reason for change.
Continuing with the foregoing example, if there is a change to the report compilation process, there is a greater danger that the printing code will break if it is part of the same class.