Nonconformity (quality)

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]

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]

• poor communication (or miscommunication)
• poor documentation (or lack of documentation)
• poor or limited training of personnel
• poor motivation of personnel
• poor quality materials (or lack of appropriate materials)
• poor quality tools and equipment (or lack of appropriate tools and equipment)
• poor or dysfunctional operating environment

References