Operational definition

An operational definition is the application of operationalization used in defining the terms of a process (or set of validation tests) needed to determine the nature of an item or phenomenon (e.g. a variable, term, or object) and its properties such as duration, quantity, extension in space, chemical composition, etc. Since the degree of operationalization can vary itself, it can result in a more or less operational definition. The procedures included in definitions should be repeatable by anyone or at least by peers.

An example of operational definition of the term weight of an object, operationalized to a degree, would be the following: "weight is the numbers that appear when that object is placed on a weighing scale". According to it, the weight can be any of the numbers shown on the scale after, including the very moment the object is put on it. Clearly, the inclusion of the moment when one can start reading the numbers on the scale would make it more fully an operational definition. Nonetheless, it is still in contrast to those purely theoretical definitions.

Properties described in this manner must be sufficiently accessible, so that persons other than the definer may independently measure or test for them at will. An operational definition is generally designed to model a theoretical definition. The most operational definition is a process for identification of an object by distinguishing it from its background of empirical experience.

The binary version produces either the result that the object exists, or that it doesn't, in the experiential field to which it is applied. The classifier version results in discrimination between what is part of the object and what is not part of it. This is also discussed in terms of semantics, pattern recognition, and operational techniques, such as regression.

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