Quality Assurance vs Quality Control

Quality Assurance (QA) and Quality Control (QC) are the processes most vital for a project’s success. However, professionals often confuse and intermingle the two.

Allow me to clarify the concepts. After reading this Quality Assurance Vs Quality Control (QA vs QC) blog post, I hope you will have a better understanding of the quality assurance and quality management processes.  

Every project has QC and QA functions. The QC section communicates and coordinates with the QA department and the organization.

Since these processes work closely together, many professionals, especially those working in small and medium-sized organizations, do not understand the differences.

I met with many professionals involved in quality management during my ISO 9001 training course a few years back. These people had different backgrounds and were working across various fields.

One man told me he was working as a QA/QC engineer in his company, and I questioned him about his responsibilities and duties.

He replied that he goes around checking that the work is going as planned. He inspects deliverables with specifications and recommends corrective action if the deliverable has deviation or the process is out of control.

I then asked him about the quality assurance part of his job. He gave me the same response.

This told me he was not aware of his quality assurance responsibilities.

Often QA or QC or QA/QC engineers are not aware of their job responsibilities, especially in small organizations, because the differences can be so murky. 

Sometimes, they don’t know the meaning of QA or QC.

This issue is prevalent in small or medium-sized organizations, where there are rarely the resources to hire both QA and QC engineers.

In such cases, the employee may possess the title of QA while working in QC and sometimes QC working as QA. Or their responsibilities and duties may be even more scrambled. 

This ambiguity needs to be corrected because it does affect the quality of the deliverable and the success of the project. 

Quality Assurance Vs Quality Control (QA vs QC)

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 discuss the differences between these concepts in detail, we have first to understand the term “quality.”

The most important and accepted definition is from Mr. Philip B. Crosby, who says simply that 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, “quality” is about meeting the customer’s requirements to see if the deliverable is fit for use.

If a product meets or exceeds the customer’s requirements, it is said to be of high quality. It is of low quality if it does not.
Please note that, regardless of the product’s grade, the quality should be high; you cannot compromise with quality for any reason.

Quality Assurance (QA)

quality assurance

Assurance is an act of providing confidence that the customer can believe in. 

QA guarantees the quality of the product, by ensuring that the output of the process is defect-free and conforms to all requirements.

Quality assurance is a process-based approach with the objective of preventing defects in deliverables while in the planning stage to avoid expensive reworks.

QA is a proactive process; it emphasizes planning, documenting, and finalizing guidelines. This helps communicate the product’s requirements and starts at the beginning of the project.

Once requirements are identified, you develop quality management plans to meet your stakeholders’ requirements and expectations.

Tools Used in the Quality Assurance Process

The following tools are used in quality management:

  • Quality audits
  • Process analysis
  • Quality management tools.

In a quality audit, a team of external experts reviews the process and procedures. If there are any discrepancies, they will suggest corrective action, and they may offer advice on improving the process.

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

In the process analysis, you analyze for 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 include an affinity diagram, a tree diagram, a network diagram, etc.

Quality Control (QC)

quality control

Quality control (QC) is a product-based approach that includes the activities and techniques for fulfilling quality requirements.

Quality control functions start at the beginning of the project. This is a reactive approach that helps find defects in deliverables. The objective of the QC process is to ensure the deliverables are defect-free and fulfill quality requirements.

The quality control process has the following objectives: finding any defects in the product, correcting them, and validating the deliverable.

QA and QC depend on each other; the quality control process receives input from the quality assurance process and provides feedback to the quality assurance process so that the quality assurance personal can validate the process.

For instance, say the project team finds a defect during execution. They will correct it, and they will send the feedback to the quality assurance team. 

This team will investigate the cause of the error and take action to ensure that it does not occur again.

After the process update, the quality control people will follow the updated process to stop the defect occurrence.

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

Tools Used in the Quality Control Process

The quality control process has three main techniques:

  • Inspection
  • Statistical sampling
  • The seven basic tools of quality

During an inspection, the deliverable is physically examined for any defects and to check it against the quality requirements.

A statistical sampling selects a random number of items from a batch to inspect them for any defects and conformance.

The seven basic tools of quality are: scatter diagrams, control charts, histograms, checklists, Pareto diagrams, cause-and-effect analyses, and flowcharts. These tools help find defects and the causes of defects.

The Differences Between Quality Assurance and Quality Control 

Quality Assurance Quality Control
Defect preventionDefect identification
Avoid defects in the deliverableCorrects defects in the deliverable
A proactive processA reactive process
Process-based approachProduct-based approach
Quality managing processesQuality verification
A quality audit is an example toolA quality inspection is an example tool

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

The Benefits of Quality Assurance and Quality Control Processes

  • High-quality output and eliminate waste.
  • Increased efficiency of operations.
  • Greater customer satisfaction, which helps your brand and grows your business.
  • Lessen rework and after-sale support are required, which saves a lot of money.
  • Encourages a high level of confidence and motivates the team.

Quality assurance and quality control are closely related; they both aim 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 have the same purpose but use different approaches. Quality assurance is process-based, and quality control is product-based. Quality assurance designs a process to create a defect-free product In contrast, quality control prevents a defective product from reaching the market.

These processes play essential roles in the success of your project. They can only be achieved effectively if the team and the organization understand their significance.

Another process, “validate scope,” might be combined with quality assurance and quality control. I have written a blog post to explain this as well.

Please visit: Quality Control and Validate Scope

Here is where this post on QA vs QC ends.

Are you involved in quality assurance or quality control activities? Please share your experiences in the comment section.