Last updated on June 3, 2016
Quality Assurance vs Quality Control – Definitions and Differences
I have been conducting PMP and general Project Management training classes for a few years. In my experience, class discussions using small day-to-day examples are the best way to learn about a topic. During my classes, I encourage students to speak up about the difference between Quality Assurance vs Quality Control. Invariably, I get contrasting and incorrect answers. Even the learned and experienced project managers are not able to distinguish between Quality Assurance vs Quality Control. Somehow, this topic is not a well understood.
In my classes, I have hard all kind of responses. Here are some of the examples:
It is safe to say that none of the above statements is correct. I believe, the major source of confusion is due to the incorrect usage of these terms in the corporate world. Somehow, different companies use these terms differently. Sometimes, professionals working for the same company use these terms differently.
But, why do we need to differentiate? Why worry? As long as the work gets done, Quality Assurance vs Quality Control can take a back seat.
I think, correct understanding of terms is important part of learning. This difference is extremely important if you are preparing for the PMP Exam – you do not want to lose on Quality Assurance vs Quality Control questions. Otherwise also, the incorrect usage of terms may lead to miscommunication & confusion and you may lose precious time.
Note I: A discussion on Quality Assurance vs Quality Control is as much relevant to Project Management as it is to Quality Management. Project Management and Quality Management are complementary topics. Quality is extremely important for any industry. Even though, the meanings of these terms is same in both the subjects, but we will look at Quality Assurance vs Quality Control from Project Management’s perspective.
Note II: The PMBOK Guide 5th edition defines two processes in Quality Management Knowledge Area – Perform Quality Assurance and Control Quality. We will differentiate between those processes as well.
Before understanding the difference, let us first define these terms.
Quality Assurance (QA)
Sometimes the standard definitions are confusing. Let us understand the “English” meaning of these terms before we look at the Project Management Definitions.
a program for the systematic monitoring and evaluation of the various aspects of a project, service, or facility to ensure that standards of quality are being met
The maintenance of a desired level of quality in a service or product, especially by means of attention to every stage of the process of delivery or production.
Simply speaking QA means that the project team has to perform preventive actions in order to ensure that the final product or service meets the defined quality standards.
You can refer to Max Wideman’s Glossary for some standard Project Management definitions of QA. The Project Management definitions are technically more appropriate, but the English definitions also convey the right meaning. Moreover, the English definitions are easier to understand.
Quality Control (QC)
the activity of checking goods as they are produced to make sure that the final products are good
A system of maintaining standards in manufactured products by testing a sample of the output against the specification.
Simply speaking QC means that the project team has to find faults & defects in the product or service.
You can refer to Max Wideman’s Glossary for some standard Project Management definitions of QC.
Now that we understand the meaning of the terms, let us detail out the difference between QA vs QC.
Difference Between QA vs QC
|Quality Assurance (QA)||Quality Control (QC)|
|QA is performed while the work is being done to create the deliverable.||QC is performed after the work has been completed and the deliverable is created.|
|QA is performed on the process to create the deliverable.||QC is performed on the created deliverable.|
|QA is all about defined processes – follow process, ensure processes are followed, analyze processes, find process gaps, suggest process improvements etc.||QC is all about created deliverables – perform testing & inspections, finding faults & defects, analyze faults & defects, suggest repairs etc.|
PMBOK Guide Processes – Perform Quality Assurance vs Control Quality
|Perform Quality Assurance (PQA)||Control Quality (CQ)|
|PQA is part of Executing Process Group. As with other Executing processes, PQA is performed as per the defined plan (Quality Management Plan & Process Improvement).||CQ is part of Monitoring & Controlling (M&C) Process Group. As with other M&C processes, CQ checks the conformance of the results of Execution activities against the plan. Specifically, CQ tests if completed deliverables are meeting the defined specifications.|
|One of the inputs, Quality Control Measurements, is an output of CQ process. Quality Control Measurements are analyzed in PQA to see if the defined processes are working well or not.||Quality Control Measurements is an output of CQ process.|
|Main techniques for PQA are Quality Audits (process audits) and Process Analysis.
||Main techniques for PQA are Inspection (checking deliverables) and Approved Change Requests Review.
|Main output of PQA is Change Requests. Change Requests are used to recommend corrective or preventive actions.||Main outputs of CQ are Verified Deliverables, Validated Changes and Change Requests. Change Requests are used to recommend defect repairs.|