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Glossary - D
 

D chart - See “demerit chart.”

Data
- Factual information used as a basis for reasoning, discussion, or calculation; often refers to quantitative information. OR A set of collected facts. There are two basic kinds of numerical data: measured or variable data, such as “16 ounces,” “4 miles” and “0.75 inches;” and counted or attribute data, such as “162 defects.”

Dead Messenger Society
- A movie title parody that prompts recognition that organizations still tend to blame the messenger who happens to bring bad news (or call attention to the organization's problems, errors or flaws).

Decision Matrix -
A matrix teams use to evaluate problems or possible solutions. For example, a team might draw a matrix to evaluate possible solutions, listing them in the far left vertical column. Next, the team selects criteria to rate the possible solutions, writing them across the top row. Then, each possible solution is rated on a scale of 1 to 5 for each criterion, and the rating is recorded in the corresponding grid. Finally, the ratings of all the criteria for each possible solution are added to determine its total score. The total score is then used to help decide which solution deserves the most attention.

Deduction - An approach to theory development based on modeling.

Defect
- (1) A defect is any variation of a required characteristic which is far enough removed from its target so as to cause customer dissatisfaction. (2) A product’s or service’s non-fulfilment of an intended requirement or reasonable expectation for use, including safety considerations. There are four classes of defects: class 1 very serious, leads directly to severe injury or catastrophic economic loss; class 2 serious, leads directly to significant injury or significant economic loss; class 3 major, is related to major problems with respect to intended normal or reasonably foreseeable use; class 4 minor, is related to minor problems with respect to intended normal or reasonably foreseeable use. (3) An occurrence such as a blemish, scratch, burn, error, or omission that appears on an object. A defect does not necessarily make the object unusable or unacceptable.

Defect
Opportunity - Any measurable event that provides the chance of not meeting a customer critical characteristic.

Defective -
(1) A defective unit; a unit of product that contains one or more defects with respect to the quality characteristic(s) under consideration. (2) A product or service flawed beyond use or acceptability.

Delayed Effects
- An acknowledgment of the fact that the effects of actions or decisions will likely not be fully observed in the immediate time frame. Managers need to take this into account when determining or evaluating strategies, or drawing conclusions about the effectiveness of managerial methods or actions. One of the lessons in this is that in organizations in which managers are frequently moved, it is common to incorrectly attribute the carry-over effects of the previous manager or managers to the manager currently in place, leading to erroneous conclusions about both the current and the previous manager's performance and ability.

Delighter -
A feature of a product or service that a customer does not expect to receive but that gives pleasure to the customer when received. Also called an “exciter.”

Demand Management - (a.k.a. Demand Forecasting) Prediction of the levels of weekly or monthly product activity over a specified time (generally about two years).

Demerit Chart - A control chart for evaluating a process in terms of a demerit (or quality score); in other words, a weighted sum of counts of various classified nonconformities.

Deming Cycle
- Plan - Do - Study - Act (PDSA) cycle. Walter Shewhart created it (calling it the plan-do-check-act cycle), but W. Edwards Deming popularized it, calling it plan-do-studyact. Also see “plan-do-check-act cycle.

Deming Prize
- A Japanese quality award for individuals and groups that have contributed to the field of quality control. OR an award given annually to organizations that, according to the award guidelines, have successfully applied companywide quality control based on statistical quality control and will continue to do so. Although the award is named in honor of W. Edwards Deming, its criteria are not specifically related to Deming’s teachings. There are three separate divisions for the award: the Deming Application Prize, the Deming Prize for Individuals and the Deming Prize for Overseas Companies. The award process is overseen by the Deming Prize Committee of the Union of Japanese Scientists and Engineers in Tokyo.

Dependability
- Collective term used to describe the availability performance and its influencing factors: reliability performance, maintainability performance and maintenance support performance. OR The degree to which a product is operable and capable of performing its required function at any randomly chosen time during its specified operating time, provided that the product is available at the start of that period. Dependability can be expressed as the ratio of time available/(time available + time required)

Dependent Events -
Events that occur only after a previous event.

Dependent Variables
- The variable, usually the process output (y) which is affected by the independent variables (x’s).

Deployment -
Dispersion, dissemination, broadcasting or spreading communication throughout an organization, downward and laterally. Also see “cascading.”

Design and Development
- Set of processes that transforms requirements into specified characteristics or into the specification of a product, process or system.

Design Control
- A set of steps focused on managing the design of a product.

Design for Disassembly (DFD) -
 A method for developing products so that they can easily be taken apart.

Design for Maintainability
- A concept that states that products should be designed in a way that makes them easy for consumers to maintain.

Design for Manufacturability and Assembly
- A simultaneous engineering process designed to optimize the relationship between design function, manufacturability, and ease of assembly.

Design for Manufacture (DFM)
- The principle of designing products so that they are cost effective and easy to make.

Design for Manufacturing and Manufacturability (DFM) - (1) Design for manufacturing (DFM) is a development practice emphasizing manufacturing issues throughout the product development process. Successful DFM results in lower production cost without sacrificing product quality. (2) DFM is the process of proactively designing products to optimize all the manufacturing functions: fabrication, assembly, test, procurement, shipping, delivery, service, and repair, and assure the best cost, quality, reliability, regulatory compliance, safety, time-to-market, and customer satisfaction.

Design for Remanufacture
- A method for developing products so that the parts can be used in other products. Associated with green manufacturing.

Design for Remanufacture -
 A method for developing products so that the parts can be used in other products. Associated with green manufacturing.

Design for Reuse
- Designing products so they can be used in later generations of products.

Design Input
- The physical and performance requirements of a device that are used as a basis for device design. [4]

Design of experiments (DOE) -
(1) A branch of applied statistics dealing with planning, conducting, analyzing and interpreting controlled tests to evaluate the factors that control the value of a parameter or group of parameters. Design for Six Sigma (DFSS): See “DMADV.” (2) An approach to product design that involves identifying and testing alternative inputs to the production of a product to identify the best mix of inputs. (3) A statistical experimentation approach that enables understanding of how the variables (factors) in a process contribute and interact to affect the output (response) of that process.

Design Record - (1) Engineering requirements typically contained in various formats; examples include engineering drawings, math data and referenced specifications. Designing in quality versus inspecting in quality: See “prevention versus detection.” (2) The process of checking designs for ­accuracy.

Design Review
- (1) A formal, documented, comprehensive, and systematic examination of a design to evaluate the design requirements and the capability of the design to meet these requirements and to identify problems and propose solutions. (2) A documented, comprehensive, systematic examination of a design to evaluate the adequacy of the design requirements, to evaluate the capability of the design to meet these requirements, and to identify problems.

Design Validation
- Testing to ensure that product conforms to defined user needs and/or requirements. Design validation follows successful design verification and is normally performed on the final product under defined operating conditions. Multiple validations may be performed if there are different intended uses. Also, establishing by objective evidence that device specifications conform with user needs and intended use(s).

Design Verification
- Review of standards, requirements and other factors to ensure that all design outputs meet design input requirements. Design verification may include activities such as: 1. Design Review 2. Performing Alternate Calculations 3. Understanding Tests and Demonstrations 4. Review of Design Stage Documents before release

Detection
- The process of inspection or looking for defects after the output has been produced. Often compared to “prevention” in which the process is improved to avoid making the defect.

Development Plan
- A plan that identifies the skills that will be required for a particular employee to move up in an organization.

Deviation
- An authorization by a customer to depart from specified requirements for a specified quantity or for a specified period of time.

Deviation Permit
- Written authorization, prior to production or provision of a service, to depart from specified requirements for a specified quantity or for a specified time.

Deviation -
In numerical data sets, the difference or distance of an individual observation or data value from the center point (often the mean) of the set distribution.

Devil's Advocate
- Reference to the role assumed by a person who takes the opposing side in a discussion in order to provide a good "test" of the prevailing argument (even though that person may not be personally opposed).

DFA
- Design for Assembly

DFM
- Design for Manufacturability. Design of product that considers the capability of the manufacturing process and the robustness of the product design to "forgive" (tolerate without affecting quality) process variation.

DFMEA
- Design failure mode and effects analysis

Diagnosis -
The activity of discovering the cause(s) of quality deficiencies; the process of investigating symptoms, collecting and analyzing data, and conducting experiments to test theories to determine the root cause(s) of deficiencies.

Diagnostic Journey and Remedial Journey
- A two phase investigation used by teams to solve chronic quality problems. In the first phase, diagnostic journey, the team journeys from the symptom of a chronic problem to its cause. In the second phase, remedial journey, the team journeys from the cause to its remedy.

Discrete Data
- Data that can only be described by levels, i.e. Pass/fail, colour. Discrete data cannot be logically subdivided.

Discrete Variable
- A quantitative variable whose set of possible values is countable. A random variable is discrete if and only if its cumulative probability distribution function is a stair-step function; i.e., If it is piecewise constant and only increases by jumps.

Discrimination - This refers to a description of the capability of a measurement system.

Dispersion - Statistics such as the range and standard deviation (sigma) are said to be measures of dispersion.

Dissatisfiers -
The features or functions a customer expects that either are not present or are present but not adequate; also pertains to employees’ expectations. Distribution (statistical): The amount of potential variation in the outputs of a process, typically expressed by its shape, average or standard deviation.

Distance Learning
- Training that is conducted in one location and is observed in a distant location through telecommunications technology.

Distribution
- (1) The population (universe) from which observations are drawn, categorized into cells, and form identifiable patterns. It is based on the concept of variation that states that anything measured repeatedly will arrive at different results. These results will fall into statistically predictable patterns. A bell-shaped curve (normal distribution) is an example of a distribution in which the greatest number of observations occur in the center with fewer and fewer observations falling evenly on either side of the average. (2) Distribution is a way of describing the output from a system of variation. The distribution’s location, shape, and spread may be evaluated by statistics such as the mean, median, sigma, and range.

Distribution Management -
A tool for deciding upon and producing the optimal quantities of products needed from each plant to supply distribution warehouses/centers with sufficient products to meet customer demand with minimal costs and risks incurred.

DMADV -
A data driven quality strategy for designing products and processes, it is an integral part of a Six Sigma quality initiative. It consists of five interconnected phases: define, measure, analyze, design and verify.

DMAIC -
A data driven quality strategy for improving processes and an integral part of a Six Sigma quality initiative. DMAIC is an acronym for define, measure, analyze, improve and control.

Document - Document is a collection of information or instructions presented to perform some activity in a process/procedure.

Dodge-Romig Sampling Plans -
Plans for acceptance sampling developed by Harold F. Dodge and Harry G. Romig. Four sets of tables were published in 1940: single sampling lot tolerance tables, double sampling lot tolerance tables, single sampling average outgoing quality limit tables and double sampling average outgoing quality limit tables. OR Plans for acceptance sampling involving four sets of tables: single-sampling lot tolerance tables, double-sampling lot tolerance tables, single-sampling average outgoing quality limit tables, and double-sampling average outgoing quality limit tables.

Downtime -
Lost production time during which a piece of equipment is not operating correctly due to breakdown, maintenance, power failures or similar events.

DPMO
- Defects Per Million Opportunities.

DPMO Calculations -
To set a common measurement system for all processes that is normalized based on the opportunities for defects in the process output. To monitor the performance of a process, department, or organization.  

DRBFM
- Design Review Based on Failure Mode - Toyota method

Driving forces -
Forces that tend to change a situation in desirable ways.

Dual Sourcing
- Using only a few suppliers for a single component.

Durability
- (1) A dimension of quality that refers to a product’s ability to withstand stress or trauma. (2) The probability that an item will continue to function at customer expectation levels, at the useful life without requiring overhaul or rebuild due to wearout.