There are a lot of terms that are specific to Lean and Six Sigma. If you are unsure about the meaning of a term, please feel free to check our Lean and Six Sigma Glossary for a definition. If you do not find the term you are looking for, please contact us. We would be happy to answer your questions, and we may add your term to the glossary in the future.

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A decision making using criteria and facts; supporting “intuition” with data; tools used include process measurement, process management techniques, and rational decision-making tools (e.g., criteria matrix).


DMAIC phase M, where key measures are identified, and data are collected, compiled, and displayed 2. A quantified evaluation of specific characteristics and/or level of performance based on observable data.

Moment of truth

Any event or point in a process when the external customer has an opportunity to form an opinion (positive, neutral, or negative) about the process or organization.


Narrowing and prioritization tool. Faced with a list of ideas, problems, causes, etc., each member  a group is given a set number of “votes.” Those receiving the most votes get further attention/consideration.

Non-value-adding activities

Steps/tasks in a process that do not add value to the external customer and do not meet all three criteria for value-adding; includes rework, handoffs, inspection/control, wait/delays, etc.See also Value-Adding Activities.

Operational definition

A clear, precise description of the factor being measured or the term being used; ensures a clear understanding of terminology and the ability to operate a process or collect data consistently.


Any product, service, or piece of information coming out of, or resulting from, the activities in a process.

Output measures

Measures related to and describing the output of the process; total figures/overall measures.