Quality Assurance vs Quality Control

It may be hard to believe, but confusion still exists regarding Quality Assurance (QA) and Quality Control (QC). We hear it all the time in our conversations with our clients. As a result, people often use QA and QC synonymously. Although, we find many ‘Quality Assurance’ groups practice quality control without knowing it.

We can categorize quality methods in software delivery into two categories:

Preventive (QA) – Proactive (shift left)
Detective (QC) – Reactive

The main distinction lies in QA’s focus on the process, while QC (testing) centers on the product. It’s important to note that both are essential, as relying on just one is insufficient.

Software Quality Control (QC) is a procedure or set of procedures intended to ensure a project or service adheres to a predefined set of quality criteria and requirements. It does not deal with the processes used to create a product. Instead, it examines the quality of the ‘end products’ and the final outcome.

The software development process and the software itself yield numerous ‘products,’ including requirements, design documents, data models, GUI screens, programs, and more. To ensure these products meet both requirements and user needs, both Quality Assurance and Quality Control are necessary.

Software Quality Assurance (QA) consists of the means of monitoring the software engineering processes and methods used to ensure quality.

QA encompasses the entire software development process. This includes requirements definition, software design, coding, source code control, code reviews, software configuration management, testing, release management, and product integration.

Common Quality Philosophies

At the project’s outset, the Product Owner frequently encounters the question, “How do you envision success?”. This predefined definition of quality is often (for better or worse) used to determine the scope of ‘testing’. Below you will see some common quality philosophies. It’s noteworthy that many of them share two common components (organization-defined and rooted in customer satisfaction):

1. The transcendental perspective – Although quality cannot be defined, you know what it is. In this view, quality is synonymous with excellence, absolute, and universally recognized. Sometimes it’s identified with craftsmanship as the opposite of mass production
2. The product perspective – Quality is a concrete, measurable attribute, given by the number of characteristics of a product/service. In this perspective, the best quality products/services will have the highest prices since each character has specific costs. Moreover, as quality is a reflection of the existence or absence of quantifiable attributes in a product or service, it can be objectively assessed.
3. The user perspective – Fitness for use; this perspective has led to the following approaches: Aggregation of very diverse individual preferences in order to define quality at a market level in a significant manner; determining a consistent positive correlation between the two key concepts: (1) Quality and (2) customer satisfaction
4. The producer perspective – The degree a product/service shows conformity with a project or specification; in this respect, quality means ‘right the first time’
5. The value perspective – Although very important, this perspective is difficult to apply because it comprises a mixture of two linked, but distinct concepts: (1) excellence and (2) value. It defines quality in a subjective, diffuse manner, as the excellence we can afford

On the other end of the quality definition spectrum are the functional and non-functional attributes some organizations use to define quality. These are less philosophical and more binary. These are things like ISO25010. This quality model establishes the criteria for assessing the quality attributes to be taken into account during the evaluation of a software product in development. ISO 25010 breaks down into 8 primary quality characteristics and 31 sub-characteristics. You can find more information at the ISO Standards site.

Connect with our Quality Assurance Experts

With all of these quality definitions, characteristics, and philosophies to consider, it might be challenging to get clarity on what quality means to you, and your organization. Don’t worry we can help. Find out more by scheduling a Quality Assessment or emailing info@trissential.com