Difference Between Quality Assurance and Quality Control (QA vs QC)

Get the answer to the most frequently asked question – What is the difference between Quality Assurance and Quality Control?

What is Quality?

Quality is meeting the requirement, expectation, and needs of the customer is free from the defects, lacks and substantial variants. There are standards needs to follow to satisfy the customer requirements. 

QUALITY ASSURANCE AND QUALITY CONTROL

What is Assurance?

Assurance is provided by organization management, it means giving a positive declaration on a product which obtains confidence for the outcome. It gives a security that the product will work without any glitches as per the expectations or requests.

What is Quality Assurance?

What is Quality Assurance

Quality Assurance is known as QA and focuses on preventing defect. Quality Assurance ensures that the approaches, techniques, methods and processes are designed for the projects are implemented correctly.

Quality assurance activities monitor and verify that the processes used to manage and create the deliverables have been followed and are operative.

Quality Assurance is a proactive process and is Prevention in nature. It recognizes flaws in the process. Quality Assurance has to complete before Quality Control.

What is Control?

What is Quality Control

Control is to test or verify actual results by comparing it with the defined standards.

What is Quality Control?

Quality Control is known as QC and focuses on identifying a defect. QC ensures that the approaches, techniques, methods and processes are designed in the project are following correctly. QC activities monitor and verify that the project deliverables meet the defined quality standards.

Quality Control is a reactive process and is detection in nature. It recognizes the defects. Quality Control has to complete after Quality Assurance.

Difference between quality assurance and quality control 1

What is The Difference in QA/QC?

Many people think QA and QC are the same and interchangeable but this is not true. Both are tightly linked and sometimes it is very difficult to identify the differences. Fact is both are related to each other but they are different in origins. QA and QC both are part of Quality Management however QA is focusing on preventing defect while QC is focusing on identifying the defect.

Quality Assurance vs Quality Control

QA vs QC

Here is the exact difference between Quality Control and Quality Assurance that one needs to know:

Quality AssuranceQuality Control
It is a process which deliberates on providing assurance that quality request will be achieved.QC is a process which deliberates on fulfilling the quality request.
A QA aim is to prevent the defect.A QC aim is to identify and improve the defects.
QA is the technique of managing quality.QC is a method to verify quality.
QA does not involve executing the program.QC always involves executing the program.
All team members are responsible for QA.Testing team is responsible for QC.
QA Example: VerificationQC Example: Validation.
QA means Planning for doing a process.QC Means Action for executing the planned process.
Statistical Technique used on QA is known as Statistical Process Control (SPC.)Statistical Technique used on QC is known as Statistical Quality Control (SPC.)
QA makes sure you are doing the right things.QC makes sure the results of what you've done are what you expected.
QA Defines standards and methodologies to followed in order to meet the customer requirements.QC ensures that the standards are followed while working on the product.
QA is the process to create the deliverables.QC is the process to verify that deliverables.
QA is responsible for full software development life cycle.QC is responsible for software testing life cycle.

Does Quality Assurance Remove Need for Quality Control?

“If QA (Quality Assurance) is done then why do we need to perform QC (Quality Control)?”

Well, this thought might come to your mind, from time to time.

If we have followed all the pre-defined processes, policies & standards correctly and completely then why do we need to perform a round of QC?

QA vs QC

In my opinion, QC is required after QA is done.

While doing ‘QA’, we define the processes, policies & strategies, establish standards, develop checklists etc. that needs to be used and followed throughout the life cycle of a project.

And while doing QC we follow all those defined processes, standards and policies that we laid down in QA to make sure that the project is maintaining high quality and the final outcome of the project at least meets the customer’s expectations.

QA_QC

QC looks at the end of the line while QA looks further down the line. QC aims at detecting & correcting the issues while QA aims at preventing the issues to occur.

QCQA

QA does not assure quality, rather it creates and ensures the processes are being followed to assure quality. QC does not control quality, rather it measures quality. QC measurement results can be utilized to correct/modify QA processes which can be successfully implemented in new projects as well.

Quality control activities are focused on the deliverable itself. Quality assurance activities are focused on the processes followed to create the deliverable.

QA and QC are both part of Quality management and these are the powerful techniques which can be used to ensure that the deliverables are of high quality and meet expectations of the customers.

QM

When we talk about software testing, it falls in the domain of quality control because it focuses on the product or application. We test the quality in order to control it. Furthermore, quality assurance makes sure that we are doing the testing in the right way.

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Example: Suppose we need to use an Issue tracking system to log the bugs during the testing of a web application.
QA would include defining the standard for adding a bug and what all details should be there in a bug like a summary of the issue, where it is observed, steps to reproduce the bugs, screenshots etc. This is a process to create a deliverable called ‘bug–report’.


When a bug is actually added in issue tracking system based on these standards then that bug report is our deliverable. This activity is a part of the QA process.

Now, suppose some time at a later stage of the project, we realize that adding ‘probable root cause’ to the bug based on tester’s analysis would provide some more insight to the Dev team, then we will update our pre-defined process and finally, it will be reflected in our bug reports as well.

Adding this extra information in the bug report to support faster & better resolution of the issue is a part of the QC Process. So, this is how QC gives its inputs to QA to further improve the QA and final deliverables.

Real-life scenario Examples for QA/QC

QA Example:

Quality Assurance

Suppose our team has to work on completely new technology for an upcoming project. Our team members are new to technology. So, for that, we need to create a plan for getting the team members trained in the new technology.

Based on our knowledge, we need to collect pre-requisites like DOU (Document of Understanding), design document, technical requirement document, functional requirement document, etc. and share these with the team.

This would be helpful while working on the new technology and even would be useful for any newcomer in the team. This collection & distribution of documentation and then kicking off the training program is a part of the QA process.

QC Example:

Quality Control

Once the training is completed, how can we make sure that the training was successfully done for all the team members?

For this purpose, we will have to collect statistics e.g. the number of marks the trainees got in each subject and the minimum number of marks expected after completing the training. Also, we can make sure that everybody has taken training in full by verifying the attendance record of the candidates.

If the marks scored by candidates are up to the expectations of the trainer/evaluators, then we can say that the training is successful otherwise we will have to improve our process in order to deliver high-quality training.

Another way to improve the training process would be collecting feedback from the trainees at the end of the training program. Their feedback will tell us what was good about the training and what are the areas where we can improve the quality of training. So, such activities are a part of the QA process.

Conclusion

Key Points:

  • In QA, processes are planned to evade the defects
  • QC agreements with the discovery of the defects and modifying them while making the product
  • QA detects weakness
  • QC detects defects
  • QA is process oriented
  • QC is product oriented
  • QA is a failure prevention system
  • QC is a failure detection system.

QA & QC both are different from each other and required as part of quality management. They should not be misunderstood as interchangeable terms. QA is process focused while QC is end-product focused.

Quality control is inspecting something (a product or a service) to ensure that it is working fine. If the product or service is not working fine, then the issue needs to be fixed or eliminated in order to meet conformance standards. So, it aims at detecting and correcting issues.

Quality assurance, on the other hand, aims at preventing the issues from occurring in the future by improving the process.

To summarize, we can say that Quality assurance does not eliminate the need for Quality control as QC lies at the very core of Quality management.

Hope this explains the difference between QA and QC.