Supplier Quality Standards Association

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Terms and Definitions

“The limits of my language are the limits of my world. All I know is what I have words for.”
~ Ludwig Wittgenstein ("Philosophical Investigations," 1953)

The terms and definitions provided herein are intended to promote consistency in understanding the concepts described in SQSA standards; as well as provide interpretive guidance for the application of requirements. In instances where the official accepted SQSA definition is protected under the copyright of another entity, a citation or reference is made to the document containing that definition.


Accumulation of Tolerances
The arithmetical sum of the maximum specified limits for both unilateral and bilateral tolerances provides the total maximum tolerance of a dimensional characteristic. Similarly, the arithmetical sum of the minimum specified limits for both unilateral and bilateral tolerances provides the total minimum tolerance of a dimensional characteristic.
Note: Where Engineers fail to calculate the "accumulation of tolerances" and/or provide a "total tolerance" for a product dimension, the finished product may not function as intended; through no fault of the manufacturing process.
An order placed for a product, after its release date, that is temporarily “out of stock”.
Note: An order placed for a product prior to its release date is an “advance purchase” or “pre-order”, and is not shipped until the product release date.
A process, in a chain of processes, that is constraining the capacity of the overall chain.
Note: There are both short-term and long-term bottlenecks. Short-term bottlenecks are temporary (e.g., equipment temporarily taken out of service for repair or maintenance, workers taking a “sick day” or planned vacations). Long-term bottlenecks are often due to equipment limitations (which may be addressed through updating / upgrading the equipment) and/or inefficiencies within the process (which may be addressed through a improvement event/project).
See JCGM 200:2012, “International vocabulary of metrology – Basic and general concepts and associated terms (VIM)”, Sec. 2.39 (
Note: A common misconception is that “calibration” means verifying conformity with a specification or adjusting the output of a device to bring its performance “within limits” of a specification. Any adjustment made to the output of a device is separate from the calibration and verification process, and must be followed by a further calibration and re-verification to determine whether the adjustment achieved the desired results.
Capacity management
The planning and direction of available resources (machinery, labor, raw materials, etc,), consistent with the abilities and limitations of the overall processes providing products and/or services, to fulfill customer requirements and established expectations.
Note: Time and Capacity are the two primary constraints in capacity management. Three types of capacity are normally understood and taken into consideration: Potential Capacity, Immediate Capacity, and Effective Capacity. For example, the “Immediate Capacity” of a process may be extended (utilizing a portion of its “Potential Capacity”) by working overtime, re-deploying workers from other areas, or hiring additional workers (full-time, part-time, temporary, or contracted). Similarly, additional or upgraded equipment may be purchased, leased, or rented to increase the “Immediate Capacity” of a process.
Commercial off-the-shelf (COTS)
Commercially available products, typically defined by industry recognized specifications and standards, sold through public catalog listings.
Source: Derived from AS9145TM "Aerospace Series – Requirements for Advanced Product Quality Planning and Production Part Approval Process" (Issued 2016-11), sec. 3.2.
Common Cause
Factors that contribute to variation and are inherent to the process.
Source: MIL-HDBK-1916, "Department of Defense Handbook - Companion Document to MIL-STD-1916" (dated 10 February 1999), sec. 3.1j.
Note: A "Common Cause" variation is normal/usual (expected), quantifiable, random variation with NO assignable root cause.

When a process is in statistical control, the only variation existing comes from common causes. Common cause variations can only be reduced by management taking action on system components (e.g., implementing countermeasures, improving equipment capability, better training).
Materials, supplies, equipment, or tools that are considered to be, or have the potential to be, expendable or used up during performance of a task.
Source: NASA MSFC-STD-3598, "Standard for Foreign Object Damage / Foreign Object Debris (FOD) Prevention" (Rev. A), sec. 3.2.2.
Note: Examples include, but are not limited to:
  • Issued apparel.
  • Safety glasses.
  • Glues, paints, sealants, solvents, tape, room-temperature vulcanized products.
  • Sandpaper, brushes, scrapers, applicators, rags, wipes. Stock items such as rivets, washers, fasteners, cable ties, and other hardware.
Action(s) required to stop the delivery/shipment of known or suspect nonconforming products and/or services, and prevent or mitigate further adverse impact to the customer.
Note: Containment actions often include, but are not limited to, identifying the necessary steps for the proper identification, isolation, and control of nonconforming product and to prevent its use or delivery throughout the supply chain from sub-tier suppliers, direct suppliers, stores, WIP, finished goods, test, and at the customer.

Some quality professionals, misinterpreting the concept, incorrectly refer to “containment” using the misnomer “short term corrective action” or “immediate corrective action”.
Unwanted material that may adversely affect component or system performance.
Source: NASA MSFC-STD-3598, "Standard for Foreign Object Damage / Foreign Object Debris (FOD) Prevention" (Rev. A), sec. 3.2.3.
Note: Acceptable contamination limits may be specified on engineering drawings. FOD is a form of large-scale contamination, not specified on engineering drawings, for which the acceptable limit is always zero.
Core Process
An activity or function that directly produces a deliverable product or service.
Note: In the case of a deliverable product, for example, it is the manufacture, processing, or assembly of components that would be the “core process”. Other processes or functions necessary for the effective operation of a core process are “support processes”. In this scenario, the supporting processes might include:
  • Marketing and Sales (gathering value stream inputs)
  • Production Planning
  • Procurement (Purchasing)
  • Receiving
  • Training
  • Calibration (Metrological Confirmation)
  • Preventive Maintenance (Planned Preventive Maintenance (PPM) and/or Predictive Maintenance (PdM))
  •  Information Technology (IT)
  • Shipping
Many companies outsource some of their “support processes” to suppliers who provide those services as their “core process” (e.g., Calibration Services, IT support).
Corrective Action
One or more actions taken to eliminate a special cause variation in a process.
Note: In order to correctly implement a “corrective action”, a distinction must first be made as to whether the nonconformity is the result of a “common cause” or a “special cause” variation in the process. Because “common cause” variation is inherent to the process, there is no assignable “root cause”. Therefore, “corrective action” can only be taken where the nonconformity was the result of a “special cause” variation in the process. If a “root cause” is identified after its classification as a “common cause” variation, then it must be re-classified as a “special cause” variation.

Second, viewing the nonconformity as a realized risk, in order for the corrective action to be effective, the likelihood of recurrence must be reduced to zero.

A common example of effective corrective action is the use of “mistake proofing”, or its Japanese equivalent “poka-yoke” (pronounced PO-ka yo-KAY). Ref:
An action taken to counteract, negate, neutralize, or offset the effects of an undesirable event.
Note: A “countermeasure” is employed where the complete elimination of circumstance, that could lead to one or more potential nonconformities, is impossible or improbable due to the nature of a process (i.e., common cause variations). Unlike a "corrective action", which eliminates the “root cause” of nonconforming conditions (i.e., special cause variations), the purpose of a “countermeasure” is to counteract, negate, neutralize, or offset the effects of a known variation occurring randomly in a process. Some monitoring systems are designed to detect trends, allowing countermeasures to be executed at predetermined set-points prior to the process producing nonconforming products/services (e.g., control/feedback loops).
Critical Characteristic (CC)
Any dimension, tolerance, finish, material composition, assembly process, manufacturing process, inspection process, installation process, mechanical feature or electrical attribute relating to a product which, if nonconforming or missing, could cause a failure or malfunction resulting in an unsafe condition.
Source: Derived from MIL-STD-100G, “Department of Defense Standard Practice for Engineering Drawings”, sec 3.17.
Critical Safety Item (CSI)
A part, assembly, installation, or production system with one or more critical characteristics that, if not conforming to the design data or quality requirements, would result in an unsafe condition.
Source: ASME Y14.100-2004, “Engineering Drawing Practices”, sec 3.
A person or entity that assigns value and purchases goods or services from a business.
Note: A “customer” can be a consumer, client, end-user, a re-seller, retailer or a distributor. In contrast to the misnomer, “Internal Customer”, a “customer” assigns value to goods and services (through the “Voice of the Customer”); and a dissatisfied “customer” has the option of discontinuing its relationship with a business. The terms “Internal Customer” or “Internal Supplier” should be avoided. Instead, these terms are replaced with "Associate", “Process Partner” (transactions between workers within the same process), "team" or "team member" to more clearly identify their role. And at a higher level, the more accurate terms "intracompany" or "intercompany" transfers should be used.
Any single nonconformance in fulfilling a requirement or failure to satisfy an established expectation.
Note: Defects may be categorized (e.g., identifying the type of defect) or classified (e.g., Minor, Major, Critical).
A product or service that fails to comply with one or more requirements or satisfy one or more established expectations (i.e., possessing one or more defects).
Factory Acceptance Test (FAT)
The formal inspection and test of a completed product, normally performed at the manufacturer‘s facility, to verify that the supplier has the ability to furnish a product that satisfies some or all of its form, fit and functional requirements.
Note: It may be impossible to fully verify compliance with all requirements until after a product is installed. In this instance, a partial FAT may be performed at the manufacturer's facility, and the remaining requirements verified upon installation. Similarly, a FAT may also be performed in defined stages of the manufacturing process. Customers will often require: (1) a representative to be present to witness the FAT, and/or (2) a copy of the results of the FAT.
First Article Inspection (FAI) / Production Process Verification
A planned, complete, independent, and documented inspection and verification process to ensure that prescribed production processes have produced an item conforming to engineering drawings, DPD, planning, purchase order, engineering specifications, and/or other applicable design documents.
Source: SAE AS9102, “Aerospace First Article Inspection Requirement”, Rev. B, sec. 3.10.

Foreign Object Damage/Debris (FOD/FOd)
1. Any damage attributed to a foreign object that can be expressed in physical or economic terms; this may or may not degrade the product's required safety and/or performance characteristics.
2. A substance, debris, or article alien to the hardware that would potentially cause damage.
Source: NASA MSFC-STD-3598, "Standard for Foreign Object Damage / Foreign Object Debris (FOD) Prevention" (Rev. A), sec. 3.2.15 and 3.2.14.
A known (identified) and avoidable risk.
Note: There are many warning signs (specified by various standards organizations) associated with hazards. For example: Biohazards, Corrosive materials, Electrostatic Discharge, Explosives, Flammable materials or substances liable to self ignite when exposed to water or air (pyrophoric), High Voltage, Low Temperature, Non-ionizing Radiation, Radioactive material, etc.
Intercompany Transfer
Work transactions that take place between two or more affiliates or subsidiaries of the same parent company.
Note: An example of an intercompany transfer would be transactions between a parent company and one of its affiliates/subsidiaries, or between two affiliates/subsidiaries under the same parent company.
Intracompany Transfer
Work transactions that take place between two or more branches, divisions, or departments within a single company.
The literal translation from Japanese is:
Kai = Change
Zen = For Better
Note: The term "Kaizen" was popularized by Masaaki Imai through his book, "Kaizen:The Key to Japan's Competitive Success" (McGraw Hill, 1986).
Measurement and Test Equipment (M&TE)
Any system or device used to measure, test, evaluate, inspect, diagnose, or otherwise examine materials, parts, supplies, equipment, or a system to identify and/or isolate any actual or potential malfunction, or to determine compliance with specified requirements (e.g., specifications; engineering drawings) and established expectations.
Source(s): Derived from U.S. MIL-STD-109C, sec. 3.85 & MIL-STD-1839D, sec. 3.1.14
Metrological Confirmation
A set of operations performed to calibrate and verify that measuring and/or test (e.g., go/no go gages) equipment conform with specifications (i.e., within maximum permissible errors).
Note: The results of a metrological confirmation may be reported digitally (i.e., "in" or "out" of tolerance) and/or contain the supporting metrological data (e.g., actual observed values, measurement uncertainties).
Metrological Traceability
Ref. JCGM 200:2012, “International vocabulary of metrology – Basic and general concepts and associated terms (VIM)”, Sec. 2.41 (
The failure of a product or service to conform with one or more specified requirements.
Source: Derived from U.S. MIL-STD-1520C, “Corrective Action and Disposition System for Nonconforming Material”, sec. 3.6
The combination of people, material, machines, tools, environment, measuring & test equipment, and work instructions necessary to produce a product or service.
Source: “United Technologies Corporation - Aerospace Supplier Quality Requirements”, ASQR-20.1, Revision: 5, sec. 3.33.
Process Associate/Partner
A department/function or individual supporting the fulfillment of a process.
Note: Process Associates/Partners are often misidentified using the misnomers of “internal customers” and/or “internal suppliers”. Businesses using these misnomers often encourage workers to focus on identifying and satisfying the "requirements" of "internal customers"... distracting staff from focusing on those "requirements" that add value (as defined by the true “customer”). Process Associates/Partners can be employees or involve intracompany or intercompany transactions. When a Process Associate/Partner is under-performing or failing to meet requirements, that Process Associate/Partner can be counseled, dismissed or, in the case of a intracompany or intercompany relationship, addressed by management.
The consistency and degree to which customer stated requirements and established expectations, directly relating to the deliverable product(s) and/or service(s), are fulfilled.

Quality Management System
The totality of controls established throughout a value stream to identify and eliminate, or mitigate, risks to satisfying customer requirements and any established expectations (commitments) relating to the provision of products and/or services.
Information (e.g., text, photograph, drawing, audio, video) collected and stored in a medium (e.g., paper, magnetic hard drive, optical disc, solid state drive (SSD)) that provides evidence of activities performed, historical events, results achieved, or statements made.
Note: The information contained in records should be evaluated to determine accuracy, completeness and objectivity or nature of bias.
Remedial Action
Action(s) taken to bring a nonconforming condition (in a product or service) into full conformance with all requirements.
Note: A remedial action most often involves "rework" (e.g., correction) of a product or revising a report associated with a service, in order to bring it into conformity with requirements; as opposed to a "repair", which would not return the product into full conformity with all requirements. However, remedial action could also mean replacing a defective product with one (of equal or greater value) that satisfies all requirements. Or re-performing a service in order for it to conform with all requirements.
A procedure which restores a product to meet its intended usage requirements through reducing, but not completely eliminating, one or more nonconformities.
Source: Derived from U.S. MIL-STD-1520C, “Corrective Action and Disposition System for Nonconforming Material”, sec. 3.12
Note: The purpose of repair is to mitigate/reduce the effect of the nonconformance. Repair is distinguished from rework in that the characteristic after repair still does not completely conform to all requirements.
Stipulated criteria that must be met or satisfied.
Residual Risk
The level (or degree) of risk remaining after implementation of controls.
A procedure applied to a nonconformance that will completely eliminate the nonconforming condition resulting in full conformance with all requirements.
Source: Derived from U.S. MIL-STD-1520C, “Corrective Action and Disposition System for Nonconforming Material”, sec. 3.13 & IAQG SCMH 3.3.
Rework Loop
Any instance in a core or supporting process, where nonconforming outputs are routinely corrected by being returned to a previous phase, stage or step in the value stream.
Note: While a “rework loop” can directly relate to product(s) or service(s) in a core process, a “rework loop” could also be repeatedly correcting procurement requirements, repeatedly replacing incorrect parts in a Kanban bin, etc. in a supporting process.
Situation or circumstance that has both a likelihood of occurring and a potentially negative consequence.
Source: API Spec Q1, "Specification for Quality Management System Requirements for Manufacturing Organizations for the Petroleum and Natural Gas Industry" (Ninth Edition, June 2013), section 3.1.19, "risk" (published by the American Petroleum Institute (API)).
Note: There are many different types of risk (e.g., financial, legal, market, operational, safety, technical). The above definition is intended to address only those risks related to satisfying customer requirements and established expectations (i.e., quality risks).
Risk Control
A risk mitigation option that seeks to actively reduce risk to an acceptable level. It entails taking action to reduce the likelihood or consequence of a risk to as low as possible to minimize potential impacts.
Source: Derived from "Department of Defense Risk, Issue, and Opportunity Management Guide for Defense Acquisition Programs", January 2017.
Risk Management
A formal, structured system for the identification, ranking (e.g. likelihood/probability of occurrence, possible effects of consequences, ability to detect), and analysis leading to decisions (e.g., actions) related to risk tolerance.
Note: Decisions relating to the risk tolerance typically include: acceptance, avoidance, eliminating the risk(s), mitigating the risk(s) - through the application of controls, sharing the risk(s), or transferring the risk(s).
Risk Mitigation
The implementation of one or more controls to reduce the likelihood/probability and/or severity of a potentially negative consequence.
Note: A control may be an improvement in detection of a potentially negative consequence either prior to its occurrence (e.g., monitoring of a process control chart) or to limit its severity (e.g., implementing an inspection point to prevent nonconforming products from progressing through the value stream).
Risk Tolerance (Level)
The level (or degree) of risk that is acceptable to management in relation to the likelihood/probability and severity of a potentially negative consequence.
Special Cause
A factor that contributes to variation and that is feasible to detect and identify.
Source: MIL-HDBK-1916, "Department of Defense Handbook - Companion Document to MIL-STD-1916" (dated 10 February 1999), sec. 3.1bb.
Note: A "Special Cause" variation is abnormal/unusual (unexpected), not previously observed, non-quantifiable variation WITH an assignable root cause.
Statistical Control
A state wherein all "special cause" variations have been removed from a process.

Support Process
An activity or function necessary for the operation of a core process.
Technical Contradiction
A situation which emerges when an attempt to solve an inventive problem by improving a certain attribute (parameter) of a technical system leads to unacceptable degradation of another attribute (parameter) of the same system..
Source: "Glossary of TRIZ and TRIZ-Related Terms" (Version 1.2) by Valeri Souchkov, "The International TRIZ Association – MATRIZ, 2018"
Note: An example of a "technical contradiction" would be where improving the strength (one parameter) of an airplane wing leads to the increased weight (another parameter) of its wing.
Russian acronym for "Teoriya Resheniya Izobreatatelskikh Zadatch", which, translated into English approximates to the "Theory of Inventive Problem Solving".
Note: TRIZ consists of "40 Inventive Principles" described at:
An authorized disposition of an article with one or more nonconformities determined to be usable to fulfill its intended purpose in its existing condition, although it does not conform to requirements originally specified in the contract, specifications, drawing or other applicable design data. (Source: IAQG SCMH 3.3)

"Unified Structured Inventive Thinking" - A methodology used to enable a problem solver to invent multiple solution concepts in as short a time as possible for real-world problems (day-to-day technical problems in all fields).
The extent to which a product or service is perceived by the market (customers) as providing utility (benefits), often measured as a monetary worth.
Note: Value is not a “constant”, as it can fluctuate due to variables such as supply and demand.
Value Stream
A sequence of activities or events required to transform inputs to outputs (e.g., a specific good, service, or experience) that a customer desires (and assigns value).
Note: Activities or events that do not contribute to the "value" assigned by a customer are "non-value added" activities or events (e.g., production of defects, rework, overproduction, under-utilization of equipment and/or personnel, unnecessary delays, unnecessary handling/movements, excess processing, excess inventory).
The act, or set of actions, performed to confirm that a process, product, service, or system (in whole or in part) conforms to its specified requirements.
Note: The words “Verification” and “Validation” are often incorrectly used… or considered synonyms. For purposes of this definition, we examined the etymology of each word. Ref. and


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