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, QA and QC are often used synonymously. Although, we find many ‘Quality Assurance’ groups practicing quality control without even knowing it.

Quality methods in software delivery can be segmented into two categories:

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

The key difference is that QA is interested in the process whereas QC (testing) is interested in the product. The truth is that both are needed as one is not enough.

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. Rather, it examines the quality of the ‘end products’ and the final outcome.

There are many ‘products’ produced from the software development process in addition to the software itself – requirements, design documents, data models, GUI screens, programs, and so on. 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 processes such as requirements definition, software design, coding, source code control, code reviews, software configuration management, testing, release management, and product integration.

At the beginning of a project, the Product Owner is often asked ‘what does success look like to you?’. 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. What’s important to note is that many of them share two of the same components (must be defined by the organization, and should be based on 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. Furthermore, since quality reflects the presence or absence of specific measurable characteristics of a product/service, it can be objectively measured
  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 that some organizations use to define quality. These are less philosophical and more binary. These are things like ISO25010. This quality model determines which quality characteristics should be considered when evaluating a software product under development. ISO25010 is broken down into 8 main quality characteristics and 31 sub-characteristics. You can find more information at the ISO Standards site.

Connect with our Experts

With all of these quality definitions, characteristics, and philosophies to consider, it might be difficult 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 connect directly with our Head of QA (and author of this blog) below.

Jeff Chartos
Head of Quality Solutions