质量保证vs Quality Control

July 26, 2020
法哈德·乌斯曼尼(Fahad Usmani)
质量保证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.

这让我想起了一个交互在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 propercorrective action如果与规格有任何偏差。

我说好的,这要照顾您工作的质量控制部分,但是质量保证呢?

He was not aware of his quality assurance responsibilities.

经常遇到担任QA或QA或QA/QC工程师的专业人员不知道自己的工作职责,即使质量保证的责任与质量控制功能之间的差异很明显。

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.”

什么是质量?

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.

如果一个产品达到或超过客户的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 thegrade, the quality should be high; quality cannot be compromised in any case.

质量保证

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.

这是一个积极主动的过程;它强调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.

在高质量的审核中,一组外部专家团队来审查过程和程序。如果有任何差异,他们会建议采取纠正措施,并且可能建议改善该过程。

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.

质量管理和控制工具包括各种示意技术,可帮助您找到想法,做出决策并确定问题的优先级。这些工具的一些示例包括亲和力图,树图,网络图等。

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.

例如,如果项目团队在执行过程中发现缺陷,他们将纠正它,并将反馈发送给质量保证团队。质量保证团队在调查了此缺陷的原因后将采取纠正措施或预防措施,以防止将来这种缺陷再次发生。

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.

质量控制过程中使用的工具

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.

七个基本质量工具是散点图,control chart, histogram, checklist,帕累托图,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.
  • 质量保证是一个主动的过程,甚至在可交付到可交付的工作开始之前就开始了,而质量控制是一个反应性过程,并且一旦您开始从事可交付方式工作,其活动就开始了。
  • 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.

Summary

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.

还有另一个过程,“验证范围”,它可能与质量保证和质量控制相结合。我也写了另一篇博客文章来解释这一点。请拜访:质量控制和验证范围.

您是否参与质量保证或质量控制活动?如果是,请在评论部分分享您的经验。

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把你的想法说出来

  • 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?

    • Hello Kaimfa,

      Both processes are interconnected. It would be better for someone if they understood both processes.

  • 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.

    谢谢,
    Dima

    • Congratulations Dima on passing the exam. I am glad that I could be of some help to you.

  • 你好法哈德,

    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.

    在财务限制下,两者中的哪一个将是一个更好的投资选择。一个人的目标/目标是证明质量保险公司提供了一种更好的方法来确保质量?或得出一个整体结论,即质量保证和质量控制同样重要。我仍然不确定,这只是我研究任务的开始。

    • 两者都同样重要并相互补充。在QA中,您定义过程,在QC中,您确保遵循它。

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

  • quality is a word with several meaning and connotation. quality can mean excellence as in,this is a quality product.

  • 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!

  • 好吧,这在这里分享了有关质量保证(QA)的如此出色而有用的信息。感谢您在此博客中发布的好主意!

  • 我工作道路CONSRUCTION监督ambiguities on both QA and QC. You really solved my confusions. Now both of them are clear for me.
    上帝这么祝福你。

  • 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

  • Thx. This post is indeed informative and crystal clear. Exactly what I needed as I start my journey as a quality assurer

  • 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!

    • Quality audit it a quality assurance function not quality control, that is why it is performed in execution phase.

      • 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.

        谢谢你!

    • 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.

    • You are welcome Annie.

      Let me know if you need any further help from me.

  • 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.

  • 哇!我只需要说出您清楚,轻松地解释差异的方式给我留下了深刻的印象。
    I am so grateful for stumbling upon your blog before my exam in 3 days! Thank you!

  • 你好法哈德,

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

    我的查询是:质量保证过程是否使用了7种基本质量工具(7个)?

    • These processes are interdependent on each other, so they may use any tool depending on the situation.

  • 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
    Basheer

    • 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!

    • 你好戴尔,

      Good Luck for your exam.

      Hope to see you here again once you pass the exam.

  • 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 :)

    问候,
    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!!

    非常感谢!

    问候,
    Abhilash VJ

    • Hi Abhilash vj

      我很高兴看到您对QA和QC的评论。它清楚地了解到,质量保证的工作是看到该产品是没有缺陷的。虽然QC正在努力确保生产的产品是根据Custome请求自由缺陷。
      最后,您喜欢您正在做的石油和天然气质量工程师。

      问候

  • Help me to answer this question …..?

    乔是一个项目经理在一个工业设计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 (8.3.2.1) 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.

    谢谢。

  • 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.

      质量保证会开发过程,因此质量控制过程的输入。

      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.

  • 你好法哈德
    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.
    问候
    Saleem Angillath

    • 恭喜Saleem通过PMP考试!

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

      Stay in touch.

      Fahad

    • Thanks Fahad,
      I can imagine that I can apply QA without QC, but I cannot imagine to apply QC without QA. What can I check or inspect if it’s not defined well ( which is a QA step) ?

      • 你好sameh。这两个过程相互补充。

        I did not understand your question well. Please elaborate.

  • 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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