Glossary
Whether you’re new to the quality and continuous improvement arena or a seasoned expert seeking detailed information on a specific quality topic, you should find what you need in our Glossary of Terms.
Explore the concepts, tools, applications and technical terms that make up the world of continuous improvement.
Dashboard
The term Dashboard is a business measurement and reporting mechanisam that is targeted at communicating business objectives throughout an organisation. The Dashboard allows everyone to see on immediately how an organisation is progressing in terms of achievement to its goals and objectives.
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Data
Data is used to describe sets of numbers, characters or other inputs that are usually used to create tables or charts which are then analysed to interpret a given situation.
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Defect
Non conformance to acceptable requirements.
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Defective
A sample or part which contains one or more defects making it unacceptable for its intended use.
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Defects per Million (DPM)
A capability measure which describes the number of defective units per million units produced.
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Defects per Million Opportunities (DPMO)
A capability measure which describes the number of defects per million opportunities for failure.
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Define for Six Sigma (DFSS)
A set of advanced tools and methodologies for significantly reducing variation as early in the development process as possible. It applies to the design of new products as well as product re-design.
Degrees of Freedom
The number of independent observations minus the number of parameters estimated.
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Deming Cycle (PDCA)
The PDCA Cycle was originally developed by Walter Shewhart, the pioneering statistician who developed Statistical Process Control in US. It was promoted by the Quality Management authority, W. Edwards Deming as a tool for tracking and guiding ones continuous improvement efforts and is known by many as The Deming Wheel. The tool emphasises and demonstrates that improvement programs must start with careful planning, must result in effective action and must move on again to careful planning in a continuous cycle.
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Dependent Variable
The Dependent Variable is the variable that one feels may be influenced or modified by some treatment or exposure. It may also represent the variable you are trying to predict and analysts would want to explain why the dependent variable has a given value. Sometimes the Dependent Variable is called the outcome variable.
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Descriptive Statistics
Descriptive Statistics are used to present quantitative descriptions in a manageable form and describe the basic features of the data in a study. They provide simple summaries about the sample and the measures and together with charts, they form the basis of quantitative analysis of data. With Descriptive Statistics you are describing the situation of what is or what the data shows.
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Design of Experiments (DOE)
Design of Experiments is a rigorous statistically based method in which to investigate and identify the relationships between key input factors and the response of a process resulting in improved optimisation and control. The most significant benefit over the traditional, change one variable at a time approach, is that the user is able to find the interactions between two or more variables and see how they affect the output. When an approach is taken which is based upon changing one variable at a time it is quite possible that these interactions will be overlooked.
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Discrete Data
Data that is based upon Count Data, such as the number of defects, number of units and so on.
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Distribution
Distribution is the Normal Distribution with a mean of zero and a standard deviation of one. It is also known as a Bell Curve because the area under the curve is shaped like a bell.
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DMAIC
A structured process improvement tool which is used as a means of approaching an issue in a structured way thus enabling solutions to be more robust and sustainable.
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DOE Pro
DOE PRO XL is a software program that allows users to conduct Design of Experiments (DOE) in a simple form. It can be used to create designs, analyse designs using multiple regression, plot results, optimise and predict. DOE PRO will support up to 26 independent variables and 10 dependent variables.
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Dot Plots
Dot Plots represent individual observations in a batch of data with symbols, usually circular dots. They are used to depict individual observations on a continuous scale and Dot Plots are in reality horizontal and one-dimensional Scatterplots where tied values are perturbed or displaced vertically.
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Downtime
In business, Downtime is denoted as production time which is lost due to planned or unplanned stoppages.
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Drum-Buffer-Rope
Drum-Buffer-Rope is term used in conjunction with Theory of Constraints (TOC) and is a method of scheduling which is aimed at balancing the flow of products in a process. D-B-R controls the flow of materials through the plant in order to produce products in accordance with market demand with a minimum of lead-time, inventory and operating expenses. The definitions of DRUM, BUFFER and ROPE are where DRUM is the schedule for the constraint, BUFFER is the protection built into the process against unknown and unplanned events and ROPE, which is the schedule for releasing raw materials to the production floor.
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Experimental Design
A formal way in which to investigate and identify the relationships between key input factors and the response of a process resulting in improved optimisation and control.