Nonconformity (quality)

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In quality management, a nonconformity (sometimes referred to as a non conformance or nonconformance or defect) is a deviation from a specification, a standard, or an expectation. Nonconformities or nonconformance can be classified in seriousness multiple ways, though a typical classification scheme may have three to four levels, including critical, serious, major, and minor. [1] [2] [3] [4]

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While some situations allow "nonconformity" and "defect" to be used synonymously, some industries distinguish between the two; a nonconformity represents a failure to meet an intended state and specification, while a defect represents a failure to meet fitness for use/normal usage requirements. [2] This can be seen in the international software engineering standard ISO/IEC 25010 (formerly ISO/IEC 9126), which defines a nonconformity as the nonfulfillment of a requirement and a defect as the nonfulfillment of intended usage requirements. [5]

Classifying nonconformity

When ensuring quality of a product or a service, classification of a nonconformity is important, as it provides an opportunity to better reduce nonconformity. [1] Many quality management practices will do this using a relatively simple three- or four-level classification system. [2] [4] For example, U.S. federal agencies such as the National Aeronautics and Space Administration have used a simple three-tier system for quality requirements of government-acquired supplies and services: minor, major, and critical nonconformance. [6] However, some industries may develop their own, custom ranking systems. An example from the automotive industry uses a 10-point system for finer granularity, where, for example, a one represents "none" (no effect), a six "moderate" (vehicle or item operable, but comfort or convenience items inoperable), and a 10 "hazardous without warning" (when a potential failure mode affects safe vehicle operation without warning). [1] Regardless of size, these classification schemes exist to help drive discovery and correction of nonconformities (and defects). [1] [4]

Sources of nonconformity

The causes of nonconformities are not unlimited and therefore determinable. Common causes for deficiencies to arise include: [1]

Related Research Articles

A quality management system (QMS) is a collection of business processes focused on consistently meeting customer requirements and enhancing their satisfaction. It is aligned with an organization's purpose and strategic direction. It is expressed as the organizational goals and aspirations, policies, processes, documented information, and resources needed to implement and maintain it. Early quality management systems emphasized predictable outcomes of an industrial product production line, using simple statistics and random sampling. By the 20th century, labor inputs were typically the most costly inputs in most industrialized societies, so focus shifted to team cooperation and dynamics, especially the early signaling of problems via a continual improvement cycle. In the 21st century, QMS has tended to converge with sustainability and transparency initiatives, as both investor and customer satisfaction and perceived quality are increasingly tied to these factors. Of QMS regimes, the ISO 9000 family of standards is probably the most widely implemented worldwide – the ISO 19011 audit regime applies to both and deals with quality and sustainability and their integration.

<span class="mw-page-title-main">Configuration management</span> Process for maintaining consistency of a product attributes with its design

Configuration management (CM) is a systems engineering process for establishing and maintaining consistency of a product's performance, functional, and physical attributes with its requirements, design, and operational information throughout its life. The CM process is widely used by military engineering organizations to manage changes throughout the system lifecycle of complex systems, such as weapon systems, military vehicles, and information systems. Outside the military, the CM process is also used with IT service management as defined by ITIL, and with other domain models in the civil engineering and other industrial engineering segments such as roads, bridges, canals, dams, and buildings.

<span class="mw-page-title-main">Software architecture</span> High level structures of a software system

Software architecture is the set of structures needed to reason about a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations.

The ISO 9000 family is a set of five quality management systems (QMS) standards by the International Organization for Standardization (ISO) that help organizations ensure they meet customer and other stakeholder needs within statutory and regulatory requirements related to a product or service. ISO 9000 deals with the fundamentals of QMS, including the seven quality management principles that underlie the family of standards. ISO 9001 deals with the requirements that organizations wishing to meet the standard must fulfill. ISO 9002 is a model for quality assurance in production and installation. ISO 9003 for quality assurance in final inspection and test. ISO 9004 gives guidance on achieving sustained organizational success.

Quality assurance (QA) is the term used in both manufacturing and service industries to describe the systematic efforts taken to assure that the product(s) delivered to customer(s) meet with the contractual and other agreed upon performance, design, reliability, and maintainability expectations of that customer. The core purpose of Quality Assurance is to prevent mistakes and defects in the development and production of both manufactured products, such as automobiles and shoes, and delivered services, such as automotive repair and athletic shoe design. Assuring quality and therefore avoiding problems and delays when delivering products or services to customers is what ISO 9000 defines as that "part of quality management focused on providing confidence that quality requirements will be fulfilled". This defect prevention aspect of quality assurance differs from the defect detection aspect of quality control and has been referred to as a shift left since it focuses on quality efforts earlier in product development and production and on avoiding defects in the first place rather than correcting them after the fact.

In the context of software engineering, software quality refers to two related but distinct notions:

<span class="mw-page-title-main">ISO/IEC 9126</span> Former ISO and IEC standard

ISO/IEC 9126Software engineering — Product quality was an international standard for the evaluation of software quality. It has been replaced by ISO/IEC 25010:2011.

Software quality assurance (SQA) is a means and practice of monitoring all software engineering processes, methods, and work products to ensure compliance against defined standards. It may include ensuring conformance to standards or models, such as ISO/IEC 9126, SPICE or CMMI.

In systems engineering and requirements engineering, a non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. They are contrasted with functional requirements that define specific behavior or functions. The plan for implementing functional requirements is detailed in the system design. The plan for implementing non-functional requirements is detailed in the system architecture, because they are usually architecturally significant requirements.

IEC 61508 is an international standard published by the International Electrotechnical Commission (IEC) consisting of methods on how to apply, design, deploy and maintain automatic protection systems called safety-related systems. It is titled Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems.

A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard.

Functional safety is the part of the overall safety of a system or piece of equipment that depends on automatic protection operating correctly in response to its inputs or failure in a predictable manner (fail-safe). The automatic protection system should be designed to properly handle likely human errors, systematic errors, hardware failures and operational/environmental stress.

ISO 26262, titled "Road vehicles – Functional safety", is an international standard for functional safety of electrical and/or electronic systems that are installed in serial production road vehicles, defined by the International Organization for Standardization (ISO) in 2011, and revised in 2018.

IEC 62304 – medical device software – software life cycle processes is an international standard published by the International Electrotechnical Commission (IEC). The standard specifies life cycle requirements for the development of medical software and software within medical devices. It has been adopted as national standards and therefore can be used as a benchmark to comply with regulatory requirements.

ISO/IEC/IEEE 29119Software and systems engineering -- Software testing is a series of five international standards for software testing. First developed in 2007 and released in 2013, the standard "defines vocabulary, processes, documentation, techniques, and a process assessment model for testing that can be used within any software development lifecycle."

References

  1. 1 2 3 4 5 Hoyle, D. (2009). "36. Corrective Action". ISO 9000 Quality Systems Handbook: Using the Standards as a Framework for Business Improvement. Routledge. pp. 687–704. ISBN   9781856176842.
  2. 1 2 3 Berger, R.W.; Benbow, D.W.; Elshannawy, A.K.; Walker, H.F., eds. (2007). "Chapter 22 B. Material Control". The Certified Quality Engineer Handbook. ASQ Quality Press. pp. 183–189. ISBN   9780873897006.
  3. ↑ Dorf, R.C., ed. (1998). The Technology Management Handbook . CRC Press. pp.  13-34. ISBN   9780849385773.
  4. 1 2 3 Mitra, A. (2016). "Chapter 8: Control Charts for Attributes". Fundamentals of Quality Control and Improvement. John Wiley & Sons. ISBN   9781118705445.
  5. ↑ "ISO/IEC 25010:2011 Systems and software engineering -- Systems and software Quality Requirements and Evaluation (SQuaRE) -- System and software quality models". International Organization for Standardization. March 2011. Retrieved 22 February 2018.
  6. ↑ "Federal Acquisition Regulation" (PDF). General Services Administration. March 2005. p. 46.103. Retrieved 22 February 2018.
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