Operationsdefinition

Operationsdefinition, also known as the operational definition, is a statement that defines a concept by the specific operations used to observe, measure, or manipulate it. The concept has its roots in the philosophy of science, notably in the work of Percy Williams Bridgman, who argued that scientific terms must be tied to measurable operations to avoid ambiguity and metaphysical assumptions.

Purpose and use: Operational definitions translate abstract constructs into observable phenomena, enabling reliable measurement, replication, and comparison across studies. They clarify how variables are manipulated or observed and how data will be interpreted, supporting transparent research design and analysis.

Construction: The process typically involves identifying the concept to be measured, selecting observable indicators or behaviors, detailing the measurement procedures and units, specifying criteria for scoring or categorization, and testing for reliability and validity. Researchers may revise definitions when measurement evidence suggests the need for refinement, and they often document the rationale for the chosen operations.

Examples: In psychology, intelligence might be operationalized as the score on a standardized IQ test; social support could be measured by the number of supportive interactions recorded over a week. In physics, temperature can be defined as the reading of a calibrated thermometer. In computer science, latency may be defined as the time from command issuance to response in milliseconds.

Relation to broader concepts: Operational definitions underpin construct validity and reliability by linking theoretical concepts to observable data. They are essential for replication and meta-analysis, but they carry risks of oversimplification, instrument bias, or varying definitions across studies. Best practices emphasize transparency, justification of chosen operations, and ongoing evaluation of measurement quality.

See also: operationalization, measurement, reliability, validity, construct validity.