(1) "...Puts communicable meaning into a concept." "An operational definition is one that reasonable men can agree on." (Dr. Deming) example: customer and supplier agree to a defined method by which an item or group of items can be determined to meet requirements or not.
(2) When applied to data collection, it is a clear, concise, and detailed definition of a measure. It ensures that those collecting data do so consistently.
(3) An exact description of how to derive a value for a characteristic you are measuring. It includes a precise definition of the characteristic and how, specifically data collectors, should measure characteristics. Used to remove ambiguity and ensure all data collectors have the same understanding. Reduces chances of disparate results between collectors after Measurement System Analysis.