To define a concept in a way that can be measured. In evaluation research, to translate program inputs, outputs, objectives, and goals into specific measurable variables.

The defining of a psychological or physical attribute by the way it is measured. For example, teacher expectation may be operationalized by the number of higher-order versus lower-order questions the teacher asks of individual students. See Attribute, Construct, Operational Definition.

The process of converting concepts into specific observable behaviors that a researcher can measure.

specifying how a variable of interest will be manipulated or measured