Quality Assurance vs Quality Control

July 26, 2020
Fahad Usmani
Quality Assurance vs Quality Control

Quality assurance and quality control are most important processes for any project, as the project’s success depends on these processes.

Every project has a quality control section to take care of these functions. The quality assurance function usually stays with the organization and the quality control section has to communicate with the organization to coordinate between these two processes.

Since these processes are connected and work in coordination, many professionals, especially those working in small and medium sized organizations, do not understand their differences.

This reminds me of one interaction when I was in my ISO 9001 training course a few years back. I met with many professionals involved in quality management. These people were all from different backgrounds and were working in various fields.

One of the guys I met told me he was working as a QA/QC engineer in his company. I questioned him about his job responsibilities and his duties.

He replied that he walks around and sees if everything is going as planned or not, checks the items for correctness, and he takes proper corrective action if there are any deviations from the specifications.

I said okay, that takes care of the quality control part of your job, but what about quality assurance?

He was not aware of his quality assurance responsibilities.

It often happens that professionals who work as a QA or QC or QA/QC engineer are not aware of their job responsibilities, even though the difference between the responsibilities of quality assurance and quality control functions is clear.

This issue is prevalent in small or medium-sized organizations where they usually do not have the resources to hire QA and QC engineers separately.

In such cases, the person may possess the title of QA while working as QC and sometimes QC working as QA, or maybe even worse. This ambiguity is not right for the project and may affect the quality of the deliverable as well as the success of the project.

Quality assurance is the process of managing the quality of the product. Quality control is used to verify the correctness and quality of the product.Before we start discussing quality assurance and quality control in detail, we have first to understand the term “quality.”

What is Quality?

The most important and accepted definition of quality is given by Mr. Philip B. Crosby which says quality is “Conformance to requirements.”

According to ISO 8402:1996 – Quality Management and Quality Assurance Vocabulary standard, “Quality is the totality of features and characteristics of a product or service that bears on its ability to satisfy stated or implied needs.”

According to ISO 9000:2000 – Set of International Quality Standards and Guidelines for Quality Management Systems, “Quality is the degree to which a set of inherent (existing) characteristics fulfills requirements.”

Simply put, you can say that “quality” is about meeting the customer’s requirements and that the deliverable being fit for use.

If a product meets or exceeds the customer’s requirements, it is said to be of high quality. However, if it does not meet its stated requirements, the product is of low quality. Please note that, regardless of the grade, the quality should be high; quality cannot be compromised in any case.

Quality Assurance

quality assurance

The meaning of assurance is surety or trust. Assurance is an act of providing confidence that you can believe in. You can say that quality assurance guarantees the quality of the product. It ensures that the output of the process is defect free and conforms to all requirements.

Quality assurance is a process-based approach; its primary objective is to prevent defects in deliverables in the planning stage to avoid rework, which is always expensive.

This is a proactive process; it emphasizes planning, documenting, and finalizing the guidelines that will be necessary to assure the quality. It helps to understand the product’s requirements and expectations, and this process starts at the beginning of the project.

Once all requirements and expectations are identified, a plan is developed to meet these requirements and expectations.

Tools Used in the Quality Assurance Process

The following tools are used in quality management: quality audit, process analysis, quality management, and control tools.

In a quality audit, a team of external experts comes in to review the process and procedures. If there are any discrepancies, they will suggest corrective action, and they may suggest an improvement in the process.

Quality audit is a great tool to ensure that the project follows best practices and approved procedures.

In process analysis, you analyze to find any improvements, discover the root cause of any problems and identify any non-value-added activities.

Quality management and control tools include various diagrammatic techniques, which help you find ideas, make decisions, and prioritize issues. A few examples of these tools include an affinity diagram, a tree diagram, network diagram, etc.

Quality Control

quality control

Quality control is a product-based approach that concerns the activities and techniques that are used to fulfill the quality requirements.

Quality control functions start right at the beginning of the project work; it is a reactive approach, which helps find defects in deliverables. The primary objective of the quality control process is to make sure that the deliverables are defect free and acceptable and based on the quality requirements.

The quality control process has the following objectives: to find any defects in the product, correct them, and validate the deliverable.

Quality assurance and quality control are dependent on each other; the quality control process receives input from the quality assurance process, and in turn, gives its feedback to the quality assurance process so that the quality assurance process can validate the operational process.

For instance, if the project team finds a defect during the execution, they will correct it, and they will send the feedback to the quality assurance team. The quality assurance team will take corrective or preventive action after investigating the cause of this defect to prevent this defect from happening again in the future.

Once the process is updated, the quality control people will follow the updated process so the defect does not recur.

The quality assurance process takes inputs from the quality control process, and vice versa.

Tools Used in the Quality Control Process

Generally, there are three techniques for the quality control process. They are inspection, statistical sampling, and the seven basic tools of quality.

In an inspection, the deliverable is physically examined for any defects and to check if it matches the requirements.

In statistical sampling, you select a random number of items from a batch and inspect them for any defects and conformance.

The seven basic tools of quality are scatter diagram, control chart, histogram, checklist, Pareto diagram, cause-and-effect analysis, and flowchart. These tools help find defects and the causes of defects.

The Difference Between Quality Assurance and Quality Control

The following are a few differences between the quality assurance and quality control processes:

  • Quality assurance focuses on defect prevention, while quality control focuses on defect identification.
  • Quality assurance guarantees that the plan was efficient to avoid any anticipated defects. Quality control helps you find defects in the deliverable and correct them.
  • Quality assurance is a proactive process which starts even before the work on the deliverable has started, while quality control is a reactive process and its activity starts as soon as you start working on the deliverable.
  • Quality assurance is a process-based approach; here you develop the process to create the product, while quality control is a product-based approach where you make sure the product is as per requirements.
  • Quality assurance involves processes managing quality, and quality control is used to verify the quality of the product.
  • A quality audit is an example of quality assurance while inspection and testing are examples of the quality control process.

Although these processes are different, they complement each other and the output of one is an input of the other.

The Benefits of Quality Assurance and Quality Control

The following are a few benefits of these processes:

  • They provide you with high-quality output and eliminate waste.
  • They increase the efficiency of operations.
  • They provide customer satisfaction, which helps your brand and helps in growing your business.
  • Less rework and after-sale support are required, which will help you save a lot of money.
  • They encourage a high level of confidence and a motivated team.

Quality assurance and quality control are closely related, and they have the same objective, i.e., to deliver a defect-free product.

Both processes are an integral part of a quality management plan and failure to apply either of them will result in a low quality product.


The quality assurance and quality control processes ensure that a product is defect-free and conforms to requirements. Both processes have the same purpose but, the approach is different. Quality assurance is a process-based and quality control is a product-based. Quality assurance designs a process so that the product created by this process is defect free, while quality control checks the product when producing it to prevent a defective product from reaching the market.

These processes play essential roles in the success of your project. Their effectiveness can only be achieved if they are well understood by the organization and the team performing the job.

There is another process, “validate scope,” which might be combined with quality assurance and quality control. I have written another blog post to explain this as well. Please visit: Quality Control and Validate Scope

Are you involved in quality assurance or quality control activities? If yes, please share your experiences in the comment section.

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Speak Your Mind

  • Very usefull, with relevent to construction sector , which is not orgnised as manufacturing we are sometimes facing non availability of competent QA /QC professional .
    Please give in details related to construction.

  • This is a very interesting and insightful write up. What I would have liked to see further is how a quality management person can apply QA and QC in an organization with diversified products and services. For example printing division and insurance division?

    Does one need to first understand the processestate express undertaking a quality audit of quality control exercise?

  • Thanks so much. I really appreciate what I have learnt on this blog and above the simplicity and relatableness of the instances. Once, thanks a lot

  • Hi Fahad,

    You are doing a great job, thanks a lot for this blog! Really helps to understand many concepts in different words (even more clear than in RITA book while, of course, the one should read RITA before the exam).

    A simple acknowledgment of the fact that quality assurance is a process-based approach while quality control is a product based approach (and therefore we apply the same for audits and inspections) allowed to me answer easily to at least 4 or 5 questions during the PMP exam yesterday.


  • Hello Fahad,

    Can we say that QA is the Manage Quality in Project Quality Management and QC is the control quality in Project Quality Management?

    Thank you,
    Mehul Parekh

  • I have a research assignment which I have to do. From what I have just read, could one formulate a research title which reads:

    Title:Study on the effectiveness of QA vs QC in a Manufacturing Environment.

    Under financial constraints, which of the two would be a better option to invest in. Where one’s aim/objective would be to prove that QA provides a better means of ensuring quality? Or coming to a holistic conclusion that both QA and QC is equally important. I am still quite unsure, this is only the beginning of my research task.

    • Both are equally important and complement each other. In QA you define procedure and in QC you ensure that it is followed.

  • Quality is the satisfaction of the users by fulfilling and/or fully functioning its purpose under specific standards.

  • Have been struggling to understand this concept of how in reality these 2 tasks are performed. Your blog helped me in clarifying the difference and their uniqueness. Very well drafted with common and simple language. Thank you!

  • well,Here are sharing such a good or informative content about Quality Assurance Training.Thanks for the publish great ideas in this blog!

  • Well, here are sharing such a great and helpful information regarding Quality Assurance (QA). Thanks for the publish great ideas in this blog!

  • I am working on road CONSRUCTION supervision with ambiguities on both QA and QC. You really solved my confusions. Now both of them are clear for me.
    God bless you so much.

  • As you said ,”In quality assurance, you plan to avoid the defect in the planning phase. In quality control, you try to find defects and correct them while making the product.”. Pmbook says quality assurance is execution process

    • In quality assurance, during the execution phase you check that if the project team is following your plans and procedure correctly.

      The statement is corrected.

  • Sir you said that in quality assurance we plan for processes, how can we say that quality assurance is an execution process

  • If Risk Audit is done in the Controlling group, why is Quality Audit done in Executing?

    I am taking the exam next week, thanks for your blogs!

      • Fahad,

        Could you please contras Risk Audit with Quality Audit? I understand “audit” to be more of an inspection, or a reactive task compared to a proactive task. Thus I would assume all audits to be in the control process group.

        Thank you!

    • Fahad,

      After working on your sample questions from your eBook, I realize Procurement Audit is in the Close Procurements group, so now there is an audit activity in three different groups. I understand now, but maybe a discussion on the different types of audits might be helpful.

      Thanks again!

  • Hi Fahad

    Really like your clear and relevant article on quality assurance.

    Quality assurance might be compared to the direct and manage process of quality control.

  • Hi Fahad,

    Thanks for this well-written article, it’s straight-forward and easier to grasp the key differences than PMBOK. Your website is a great tool for me in preparing PMP exam.

  • i am looking for an affordable online courses on Quality management, six sigma or any other related courses. kindly provide links.

  • I am reading all your PMP Certification Exam Study Notes and they are very useful and clear. I am preparing to take the exam in about 2 months, I will read every note but if you have more tips, I would really appreciate them!

    Thanks for help us!

    Pura vida (I am from Costa Rica)

    • You are welcome William.

      You can download my free eBook on A2z on PMP exam and go through it. This book will help you in preparing the exam.

      Let me know if you have any specific question.

  • Wow! I just have to say how impressed I am with the way you explain the differences clearly and easily.
    I am so grateful for stumbling upon your blog before my exam in 3 days! Thank you!

  • Hello Fahad,

    QA process using any tool of Quality management and control quality process.

    My query is : whether Quality Assurance process is using 7 basic quality tools(any of 7) ?

  • Assalaamu alaikkum Fahad,
    I just joined in one of the IT company as QA Engineer. The company develops website required for one of the university. There is no QA department as of now. As QA Engineer what are the process that i should introduce here.

    Thanks and Regards

    • Wa-Assalam Basheer,

      First of all you should check all procedures. There must be some procedures. Go and review those procedures, and check if they are following these procedures.

  • Today I can say I am QA/QC inspector but after reading your blog not before.
    I love your comprehensive words which very simple & understood for all.
    I love ? with fahad usmani blog.

  • Going for exam in next 2 days…. I must say your articles and blogs are really helping thanks for great work!

  • Hi Fahad,
    Just wanted to say the super work you are doing by providing clear info in your blogs. I just came to know about this website yesterday, one day before my exam… I spent about 2 – 3 hours reading all your articles, which made concepts crystal clear and I passed PMP today. Keep up the excellent work 🙂

    Prasanna Kumar K R, PMP

  • Hi Fahad,

    I’m a Recruitment Consultant in the oil & gas industry.

    This blog is fantastic and very well explained!!

    Thank you very much!

    Abhilash VJ

    • Hi Abhilash vj

      Iam glad to see you comments on qa and qc. Its clear understand that qa works of to see that the product is defect free.While qc is working to make sure the product to produced is to free defect according to the custome requests.
      Lastly have liked what you are doing oil and gas quality engineer.


  • Help me to answer this question …..?

    Joe is a project manager on an industrial design project. He has found a pattern of defects occurring in all of his projects over the past few years and he thinks there might be a problem in the process his company is using that is causing it. He uses Ishikawa diagrams to come up with the root cause for this trend over projects so that he can make recommendations for process changes to avoid this problem in the future. What process is he doing?

    A. Plan Quality

    B. Perform Quality Assurance

    C. Perform Quality Control

    D. Qualitative Risk Analysis

    I found that answer is B, but why ?….In PMBOK, under Quality Control ( cause and effect daigram’s are explained …..so doesn’t it fall under Quality control …?

    Thanks in advance.

    • See what the Joe is doing. He is only reviewing the processes used by his company so that the defects (occurred in past projects) could be removed. This is the job of quality assurance to develop a process in such way to avoid any defect.

      In Quality Control Process, the project manager takes the sample or randomly checks the process in running project.

      Therefore, the answer B is correct.

  • Fahad,

    Thanks a lot for your reply. It clears my doubt.

    What is your suggestion on taking on-line training? Now, I am doing the preparation on my own and don’t know whether i am in the correct direction. Any suggestions you can give would be appreciated.


  • Fahad,

    I do find your articles good. For some reason, I am not able to understand this article. Can you please help me?

    I understand that the QA ensures that the processes are set correctly to develop the product and the QC ensures that the final product is as per the requirements or not. Is my understanding correct?

    I did not understand how QA takes inputs from QC and QC takes inputs from QA. Can you give me an example? Thanks for your help.

    • Hello Ravindra,

      Your understanding is correct.

      Quality Assurance develops the procedures, hence input for the Quality Control process.

      During Quality Control, if you see that certain procedure needs some improvement or causing any trouble, then you can provide feedback to Quality Assurance to improve the procedures, hence input to Quality Assurance.

  • Hello Fahad
    I passed the PMP in first attempt. Your blog has helped me a lot in preparing for the exam. Thank you very much. Yours is an outstanding blog and very informative for all PMP aspirant and to others who are interested in PM. Well written and informative. Still i’m following your blog for latest articles on PMP. All the best and expecting more from you.
    Saleem Angillath

    • Congratulations Saleem for passing the PMP Exam!

      I hope this certification will help you to grow your career. Thanks for sharing your happiness here at PMSC.

      Stay in touch.


  • Thank you for posting your blog and sharing your insights and well organized thoughts and explanations. I wish I had come across your blog earlier in my travels, for today I failed my first attempt at passing the PMP exam. I was ill prepared, was too dependent on self-study via an internet website and life happens too often when one is trying to dig a hole and study in it…life always finds you to drag you away from all the fun of studying. Anyhoo, love your writing style which is not too pedantic and is not a repeat of what is found in the PMBOK which is a dread of a read for me. I never took the time to really discern between the two and it came to haunt me today.

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