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Key Terms

This Page Contains key terms from T-Z.

Term	Definition
*Upstream*	Processes (tasks, activities) occurring prior to the task or activity in question.

*Value-adding activities*	Steps/tasks in a process that meet all three criteria defining value as perceived by the external customer: 1) the customer cares; 2) the thing moving through the process changes; and 3) the step is done right the first time.
*Value-enabling activities*	Steps/tasks in a process enabling work to move forward and add value to the customer but not meeting all three of the value-adding criteria; should still be scrutinized for time and best practices-can it be done better?
*Variation*	Change or fluctuation of a specific characteristic which determines how stable or predictable the process may be; affected by environment, people, machinery/equipment, methods/procedures, measurements, and materials; any Process Improvement should reduce or eliminate variation. See also Common Cause; Special Cause.
*Voice of the Customer, or VOC*	Data (complaints, surveys, comments, market research, etc.) representing the views/needs of a company's customers; should be translated into measurable requirements for the process.
*X or Input*	Variable used to signify factors or measures in the Input or Process segments of a business process or system.
Y	Variable used to signify factors or measures at the Output of a business process or system. Equivalent to "results." A key principle of Six Sigma is that Y is a function of upstream factors; or Y = f(x).
*Yield*	Total number of units handled correctly through the process step(s).

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