Operational definition: What is it?

An operational definition, when applied to data collection, is a clear, concise detailed definition of a measure. The need for operational definitions is fundamental when collecting all types of data. It is particularly important when a decision is being made about whether something is correct or incorrect, or when a visual check is being made where there is room for confusion. For example, data collected will be erroneous if those completing the checks have different views of what constitutes a fault at the end of a glass panel production line. Defective glass panels may be passed and good glass panels may be rejected. Similarly, when invoices are being checked for errors, the data collection will be meaningless if the definition of an error has not been specified. When collecting data, it is essential that everyone in the system has the same understanding and collects data in the same way. Operational definitions should therefore be made before the collection of data begins.

See also:
>Operational definition: What does it look like?
>Operational definition: When is it used?
>Operational definition: How is it made?

The above article is an excerpt from the "Operational definition" chapter of Practical Tools for Continuous Improvement Volume 1 Statistical Tools. The full chapter provides more details on creating operational definition. This reference book is available from PQ Systems.