Demystifying Quality
As an IE (industrial engineer), the concept of Quality was at the core of every thought, deed, and utterance, whether on or off the clock.
As a microbiologist/geneticist, quality was paramount to ensuring months of research and hard work wouldn't end up in the trash or the burn pile.
As an ECE (electrical & computer engineer), quality was still important, but there were more equally-important priorities like timing, cost reduction, etc.
As a software engineer, "quality" became more of an abstract afterthought. Burning down backlogs by duct-taping Frankenstein's Code often took precedence over minutia like proper verification and validation, or even documentation.
As a cybersecurity engineer, quality (or more precisely, lack thereof) meant eternal job security.
And "quality" meant something different to me as a lawyer, educator, military officer, real estate professional, etc.
Thankfully, there are well-established standards around quality management in certain industries that if followed properly, can help create the appropriate model for your organization and field of practice. While all models are wrong, some of these models can be quite useful at times.
Introducing QE, QA and QC
Quality Assurance (QA), Quality Control (QC), and Quality Engineering (QE) are three critical aspects of product development and management. Though often used interchangeably, they have distinct roles and objectives. Understanding the differences between QA and QC within the broader context of QE is essential for any organization focused on delivering high-quality products or services.
While QA focuses on preventing defects through process-oriented measures, QC involves detecting defects through product-oriented inspections and tests. Both are integral to QE, which seeks to embed quality into every aspect of product design, development, and production. By understanding and effectively implementing QA, QC, and QE, organizations can achieve higher standards of quality and customer satisfaction.
History of QA and QC
Quality has been defined as fitness for use, conformance to requirements, and the pursuit of excellence. Even though the concept of quality has existed from early times, the study and definition of quality have been given prominence only in the last century.
1920s: Quality Control
Following the Industrial Revolution and the rise of mass production, it became important to better define and control the quality of products. Originally, the goal of quality was to ensure that engineering requirements were met in final products. Later, as manufacturing processes became more complex, quality developed into a discipline for controlling process variation as a means of producing quality products.
1950s: Quality Assurance and Auditing
The quality profession expanded to include the quality assurance and quality audit functions. The drivers of independent verification of quality were primarily industries in which public health and safety were paramount.
Quality Engineering (QE)
QE is the overarching discipline that encompasses both QA and QC. It involves the application of engineering principles to the design and implementation of systems for quality assurance and control. QE aims to integrate quality practices into every stage of product development and maintenance. This holistic approach ensures quality is not just inspected in but is built into the product from the ground up.
Quality Assurance (QA)
QA is a process-oriented approach that focuses on preventing defects in products or services. It's about ensuring that the methods, techniques, and processes used in production are designed and implemented in such a way that they will reliably produce high-quality results. QA is proactive, aiming to improve and stabilize production (and associated processes) to avoid issues before they occur. Key elements of QA include:
Quality Control (QC)
QC, on the other hand, is a product-oriented approach. It involves the inspection and testing of products to identify defects after they have been produced. QC is reactive, aiming to identify and fix issues after they have occurred. It ensures that the output — whether a product or a service — meets the quality standards set by the organization. Key aspects of QC include:
Does QA encompass QC?
According to the American Society for Quality (ASQ), QC is a subset of the QA activities.
"Quality assurance and quality control are two aspects of quality management. While some quality assurance and quality control activities are interrelated, the two are defined differently. Quality assurance relates to how a process is performed or how a product is made, quality control is more the inspection aspect of quality management.”
The International Organization for Standardization (ISO) also distinguishes between the two but highlights their complementary nature. In the ISO 9000 family of standards, which are among the most widely used quality management standards in the world, QA and QC are described as integral parts of quality management with distinct roles. QA is focused on providing confidence that quality requirements will be fulfilled, while QC is focused on fulfilling these requirements.
Figure 1 shows ISO 9000 definitions from ISO 9000:2015: Quality management systems - Fundamentals and Vocabulary.
It is important to note that while QC is often considered a subset of QA, they are distinct in their focus and activities and should not be confused as one (i.e., just because QA processes have been implemented, it should not be automatically assumed that the QC subset of those QA processes have also been properly implemented, as the latter function requires its own focus, resourcing, and monitoring).
To reiterate what was previously stated in this article:
While QA is a process-oriented approach aimed at preventing defects and ensuring quality in the production process, QC is a product-oriented approach that involves inspecting and testing the end product to ensure it meets quality standards.
In summary, while QC is often viewed as a subset or a component of QA, it is distinct in its specific focus on the inspection and testing of products or services to identify defects. Both are essential components of an overarching quality management system.
What’s the difference between QE and QS?
Figure 1 from ISO 9000 references QC as part of QA as part of a Quality System (QS). QE and QS are similar, but distinct concepts in the field of quality management, each serving a specific purpose and function.
While QE is concerned with the technical engineering aspects of quality in products and processes, QS refers to the comprehensive set of procedural practices an organization uses to ensure and manage quality in its operations. Both are integral to achieving high standards of quality but operate at different levels within an organization.
Since the distinction can be confusing, let’s break them down even further:
Summary of Key Differences between QE and QS
References
The following references contain a fairly comprehensive overview of the topics discussed above. You can also search these articles, case studies, and publications for quality assurance and quality control resources.
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