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I'm having a hard time concisely explaining to some people what the difference between the two are. Also, I not totally sure what the scope and detail of quality assurance entails.

Quality control is the process of finding defects in a product. Quality assurance architecting processes to prevent defects.

Are these correct statements?

If they're false, could someone please elucidate a clear and effective way of explaining the differences?

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  • Yes, mainly the idea is this.
    – MMMM
    Nov 28, 2012 at 17:38

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My mneumonic is that Quality Assurance is a Process (spot the double 's' in each). Quality control is testing.

If you search on QA vs QC you'll get a number of sites; I happen to find these rather clear:

Quality assurance is about engineering “processes“that assure quality. Now let’s try to understand it better! Infostretch

Quality Assurance is process oriented and focuses on defect prevention; while quality control is product oriented and focuses on defect identification. Diffen

QC: controlling / validating the quality of the project outputs QA: assuring the appropriate processes are being employed on the project based on the quality control results PassionatePM the text on that page is a bit dense, but very useful from a PMP point of view

Quality Control is product/service testing. Quality Assurance is process checking/audit.
Quality Control is checking to ensure that you build the right product (Testing).
Quality Assurance is checking to ensure that you build the product right (Process Audit). pmzilla there are a few more answers on that page, including some examples. worth a look

Accordingly to the PMBOK Guide, Fourth Edition, Perform Quality Assurance is the process of auditing the quality requirements and the results from quality control measurements to ensure appropriate quality standards and operational definitions are used. Whereas, Perform Quality Control is the process of monitoring and recording results of executing the quality activities to assess performance and recommend necessary changes. Deep Fried Brain Always a good study site. This isn't as plain language as I would like, but it is, I think, more accurate than the others

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  • This is the case in pharma world QC. is there to find and rectify problems at a production team, they will typically do a 100% check on "output" (e.g. experimental and manufacturing data) to make sure that it is accurate and meets specifications. In contrast, QA is there to ensure that overall quality systems are functioning as advertised. This boils down to making sure that whatever comes out of QC is "correct" to a predefined level (e.g. levels of active ingredient in the drug are between X and Y) through audit of some % of the data.
    – Doug B
    Nov 28, 2012 at 21:24
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I would like to start from their name. Quality assurance - it's a support of an application/project, which assumes that every quality requirements will be checked at the end of the project. The assurance may include the whole procedure, the logistic of the testing and fixing every bug and problem. It can be also preventing a problem and implementing quality systems too.

Quality control - is the procedure which has to be taken to fulfill a test. The test's result is irrelevant, the quality control refers to the testing phase.

I haven't find any online or printed argument for the following, it's only my experience: quality assurance includes quality control. However, quality control is a very important part of the quality assurance, but it's not everything. When you are talking about quality assurance, you refer to the procedure which has to be taken, from the good development and application projecting, even until the bug fix and project finalization.

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Just to add more words to help clarify: QA is proactive--creating the capability to reduce the defects in development. QC is retroactive--finding the defects already created to fix.

Think of QA as risk mitigation while QC is risk contingency.

I differ in meszar's answer only in that QC is NOT part of QA, in my view. Two different capabilities, different skill sets, different methods, different level of investments.

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  • Interesting. I've always heard that quality control, or "testing", was part of a larger quality assurance strategy. Also, in my experience, testing, if done right, can help eliminate defects before they're found, such as when using unit tests in software to detect if some change will break a process. It's still testing, but it's also very proactive at the same time. With that said, I don't use this form of testing as much as I'd like. ;)
    – jmort253
    Nov 29, 2012 at 4:11
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    I think both QA and QC are part of quality management or surveillance. It appears on the surface to be splitting hairs on a naming convention. But as I wrote above, these two capabilities do different things, with different results and different triggers. But really it comes down to what makes sense to you. Breaking it up like I do just makes sense to me...but it might just be me. :)
    – David Espina
    Nov 29, 2012 at 14:29
  • Nice clarification! As for 'QC is not part of QA', I would disagree. I have seen the assertion that QC was part of QA many times also. Just as all the other QA steps will assure quality, doing QC is just another step to guarantee further quality as well. I've seen an organization where their QA process was so elaborated and religiously applied, that they did very limited actual QC and yet their products was top quality (my opinion) and had very little bugs (asserted by clients).
    – Jeach
    Dec 3, 2012 at 22:40
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"Quality Control" is the sum of planned and executed internal processes for delivering to specifications. "Quality Assurance" is the activity of verifying that the QC processes are being followed.

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Quality Assurance would be your philosophy or mission statement, if you will, that explains how you assure that quality is part of your process.

Quality Control would be the detailed methodology and steps taken which help ensure quality is built into your end result.

In practice, Quality Assurance would include activities that are taken to confirm that Quality Control measures are being properly executed. In that respect, I think of QA as an audit of QC and I think of QC as sort of a gatekeeper to catch issues before the end product is "out the door".

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Quality Control is when you open a box of Lime Jell-O and find one packet and not two. Quality Assurance is when that Jell-O tastes like lime.

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    Quality Assurance is also making sure that finding only a single packet in a box of Lime Jell-O is a rare to non-existent situation.
    – Bart van Ingen Schenau
    Oct 31 at 8:05

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