Software Quality Assurance vs. Quality Control

quality assurance and quality control concept

If you're in the IT industry, you've no doubt come across them. You've also probably noticed that many C - level executives and customers – don't understand the difference between these terms. They often go as far as referring to them as the same processes, which they are not. Quality assurance is a proactive process that starts even before the work on the deliverable has begun. In contrast, Quality Control is a reactive process. Its action starts as soon as you start working on the deliverable. For many service organizations, the concept of quality control may be a foreign term because there is no quantifiable product to inspect and control. The quality assurance function in a service organization may not include quality control of the service. Still, it may consist of quality control of any products involved in providing the service.

As with most organizations here at Bydrec, it doesn't matter who you are or what you do; quality control will be part of your job. You will always (hopefully) check your work to make sure it doesn't go out with errors.

Quality Software

To ensure published software is safe and functions as required, the concept of software quality was introduced. It is often defined as "the degree of conformance to explicit or implicit requirements and expectations." These so-called explicit and implicit expectations relate to the two basic levels of software quality:

Functional – the product's compliance with functional (explicit) requirements and design requirements. This part focuses on the real use of software, from the point of view of the consumer: its features, performance, ease of use, absence of defects.

Non-Functional – system's inner traits and architecture, i.e., structural (implicit) requirements. This includes code maintainability, understandability, efficiency, and security.

Simultaneously, functional aspects can be guaranteed through dedicated quality management activities, including quality assurance, quality control, and testing.

Quality assurance is very process-oriented. It's all about preventing defects by ensuring the processes used to manage and create deliverables work. QA is about engineering processes that guarantee quality is achieved effectively and efficiently.

Quality control is product-oriented. It is the function of software quality that governs the result is what was expected. Quality control can be likened to having a senior manager walk into a production department of an auto plant and pick a random car for an examination and test drive. Testing activities, in this case, refer to the process of checking every joint, every mechanism separately, as well as the full product, whether manually or automatically, conducting crash tests, performance tests, and actual or simulated test drives. A crucial part in understanding the role of QC in your organization is to recognize that checking work is as far as QC goes.

While QA is proactive, QC is reactive. QC identifies bugs by inspecting and testing the product. This involves examining the result against a predetermined set of requirements and authenticating that it meets those requirements. Historically the simplest form of quality control was a sketch of the desired item. If the illustration did not match the item, it was rejected in a simple go/no go procedure. However, manufacturers soon found it difficult and costly to make parts precisely like their depiction; hence around 1840, tolerance limits were introduced. A design would function if its components were measured to be within limits.

QC aims at detecting and correcting any issues. In contrast, QA aims at preventing the problems from occurring in the first place.


Another way to understand this distinction is actions vs. results. QA involves the steps which create the product, while QC is focused on the resultant product. Several examples of each type of activity are detailed below.

QA Processes:

  • Documentation
  • Audits
  • Supplier management
  • Personnel training
  • Change control
  • Investigation procedures

QC Procedures:

  • Batch inspection
  • Product sampling
  • Validation testing
  • Laboratory testing

Software testing falls in quality control (QC) because it focuses on the product or application, i.e., we test the quality to control it. Quality assurance (QA), on the other hand, makes sure that we are doing the testing correctly. Examples of QC can include technical reviews, software testing, and code inspections.

  • 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 and QC are both parts of Quality management. These are the powerful techniques used to ensure that the deliverables are of high quality and meet customer expectations. In The End, both QA and QC are required for a successful project. When used together, they can help detect inefficient processes and identify bugs. Additionally, QA and QC can help to develop and deliver a consistently high-quality product to your customers.

If applied to car manufacturing, having a dedicated quality assurance process means that every team member understands the requirements. They are then performing their work according to the commonly accepted guidelines. Namely, it is used to make sure that every single action is completed in the right order. Every detail is implemented correctly. 

There's no one right way that all teams should operate, but it is essential to use processes. Depending on the size of your organization, that could be an easy task or a difficult one. Large enterprises will have established methods for getting new processes approved and employed, such as testing small teams and expanding. However, it's as straightforward as introducing your team to the set of procedures for small businesses, for example, a method for testing, a tracking system for issues.

Summing up, it's impossible to say whether QA or QC is more valuable than the other. QA involves establishing standards and processes to create a safe, effective method. QC activities validate the product. While every project needs quality control, not everything needs quality assurance. With QA, it's a question of optimizing the process, not the output.  For one-person development teams, that means putting out clean code and then QC it on their own; QA isn't something you need to waste time on.

It is why we believe having the right team in place for business-critical applications makes getting to market with your product or service more determinable. Here at Bydrec, our passion is talented people. Our network of developers includes quality analysis and testing specialists, UI and UX designers, mobile developers, and server administrators. For more help and an in-depth discussion of your needs, call us on 888-864-3124.

Topics: quality assurance


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