An operational definition specifies how a concept will be measured or manipulated within a particular study. It translates abstract ideas into concrete, observable procedures. For example, instead of simply stating “stress,” an operational definition might describe it as “a score on the Perceived Stress Scale” or “cortisol levels measured in saliva.”
The establishment of explicit measurement procedures is crucial for clarity, replicability, and validity in research. It reduces ambiguity, allowing other researchers to understand and replicate the study accurately. This standardization fosters consistency across studies and facilitates the accumulation of knowledge. Furthermore, it enhances validity by ensuring that the researcher is actually measuring the intended concept, rather than something related or tangential.