Operational Definition
A clear, objective, and measurable description of a target behaviour.
An operational definition describes a behaviour in terms that are so precise that any two observers can watch the behaviour and agree on when it is occurring and when it is not. It strips away subjective labels (like 'angry', 'manipulative', or 'oppositional') and focuses entirely on observable physical actions (e.g., 'screaming louder than conversational volume for more than 3 seconds' or 'striking another person with an open palm').
Writing operational definitions is the critical first step in conducting functional assessments, taking reliable ABC data, and monitoring progress in a Behaviour Intervention Plan (BIP). Without them, data collection becomes subjective and inaccurate.
Frequently Asked Questions
What is an operational definition?
An operational definition is a clear, objective, measurable description of a behaviour, written so precisely that any two observers would agree on whether it is happening. It replaces subjective labels like 'aggressive' with observable actions.
Can you give an operational definition example?
Instead of 'Sam is disruptive', an operational definition reads: 'Sam calls out - any vocalisation above conversational volume directed at the class - without raising his hand.' Another: 'hitting - striking another person with an open or closed hand.' Each describes only what an observer can see or hear.
What is an operational definition in ABA?
In applied behaviour analysis, an operational definition is the precise description of a target behaviour that makes reliable measurement possible. It is the first step before taking ABC data, calculating inter-observer agreement, or monitoring a behaviour intervention plan.