QA, QC and Testing ...

In an earlier blog entry that talked about QA (Quality Assurance) and QC (Quality Control), I said that testing was a QC activity. Recently I received a message that asked, "If QC is the same as testing: In what way, by means of testing, are you controlling the quality?"

Software Testing is one of the QC techniques. Other QC techniques include,  inspections, reviews, walk-throughs of work products like requirements, designs, code and documentation.

QA aims to assure that quality work and quality deliverables will be built in before work is completed. QA focuses on the ability of a process to produce or deliver a quality product or service. The intent of QC is to determine that quality work was done after the work has completed. For software the QC function may involve checking the software against a set of requirements and verifying that the software meets the defined requirements. QC examines the results of a process to determine the degree to which it conforms to expectations. The "control" in QC involves detecting problems with a product, or catching "poor quality" before shipping to customers. Looking at it another way, when QC finds instances of "poor quality", it implies that the group has spent resources and time to produce a product that has poor quality built in.

QC includes all tactical activities necessary to produce a quality product or service, while QA looks at quality from a strategic perspective. QC focuses on identifying problems after they occur. QA is focussed on preventing problems from occurring. Inputs from QC may feed into the QA process. For example when QC finds recurring issues in any area, QA can look at improving processes involved in producing that functionality or feature to minimize occurrence of similar issues in that area going forward.

Regarding the debate on whether it is appropriate to call testing as either QA or QC, i tend to agree with Michael Bolton's view about testing & testers: "We don’t own quality; we’re helping the people who are responsible for quality and the things that influence it. “Quality assistance; that’s what we do.
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