Studying this subject extensively, the most books state the following:
- Quality Assurance: prevention activity. Act of inspection, reviewing..
- Quality Control: testing
While there are some exceptions that mention that QA deals with just processes (planning, strategy, standard application etc.) which is IMHO much closer to real QA, yet I cannot find any good reference in Google Books.
I believe that inspections, reviews, testing is all quality control as it is about checking products, no matter if it is the final one or work products. The problem is that so many authors do not agree.
I would be grateful for detailed explanation, ideally with a reference.
- Quality Assurance is process compliance. It has nothing to do with testing, except for its planning. QA personnel will decide what test methodology to use, how to test, who will test, how to report. It checks that processes being used on the project are appropriate, correctly implemented (standards, procedures, conventions). It says what we should do in order to make a quality product.
- Quality Control is about checking the output, which is any work product produced by any process. This means that QC checks for conformance with specifications, standards…
Saying that QA tools are reviews and inspections is misguided. These activities need an output that has been done as a result of a process: so it is just a quality control (static, dynamic or both).
Quality Control also belongs within the Quality Assurance domain (it is driven by it and provides a feedback), hence testing is sometimes said to be QA (actually it can be thought as of one indirect QA activity).
EDIT: I would add that both are part of Quality Management. I would not agree that Quality Assurance overisghts verification as QA defines and measureses only processes. Verification is checking product by static methods, hence it is Quality Control. But I concur that the gray area is really confusing and enables a lot of possible intepretations.
3
I think this is an artificial distinction. Inspection, reviewing, and testing are all activities designed to ensure quality of the product.
On the other hand, it may be meaningful to categorize these activities based on who performs them. In software development unit tests and code reviews are typically done by developers, while manual testing and possibly integration testing are typically done by QA people (aka Quality Engineers, aka testers, etc.). However, there are always exceptions: you may have QA people who help write unit tests, or you may have developers running manual tests. Also, if you have an extensive test infrastructure (e. g. dedicated machines, a complex build system, etc.) you might have people whose job is to maintain it. Also, companies who can afford it often have usability specialists who help design and test user interfaces.
So, IMHO, QA, QC, and even “quality engineering” refer to the same thing, and trying to split hairs and come up with fine distinctions here is a waste of time.
5
In light of your progression of questions, I guess the TL;DR; answer is:
- Quality Assurance == Oversight of the Verification activity
- Quality Control == Oversight of the Validation activity
And yes, that is deliberately embracing the ambiguity and grey area between Ver and Val
🙂