Operational definition
An operational definition describes a target behavior in observable, measurable terms so that different observers can agree on when it does and does not occur.
An operational definition states exactly what the behavior looks like, not what the person is thinking or feeling. A good definition is objective (refers only to observable actions), clear (can be read and repeated by a new observer), and complete (says what counts and what does not). It usually includes the onset and offset of an episode and often lists examples and nonexamples.
For instance, "aggression" is too vague to measure. An operational definition might read: "Hitting: any instance of the client's open or closed hand making contact with another person's body with enough force to make an audible sound. Excludes high-fives and accidental contact during play." With that definition, two RBTs watching the same session should record the same number of hits.
Operational definitions are the base of reliable data. If each RBT interprets a behavior differently, the data reflect who was observing rather than what the client did, and interobserver agreement will be low. RBTs use the definition the supervisor wrote and ask for clarification if a case does not seem to fit. Applying it loosely, or changing it without the supervisor, makes data from different sessions and observers impossible to compare.
Example and non-example
| Example | "Out of seat: any time both of the student's buttocks are off the chair seat for 3 seconds or more, ending when the student is seated again" is an operational definition. |
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| Non-example | "The student is defiant and has a bad attitude" is not an operational definition, because it names an interpretation rather than observable actions. |
Don't confuse it with
| Behavior | Behavior is what the person does; an operational definition is the written description that lets observers measure it consistently. |
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| Dead man's test | The dead man's test checks whether something is behavior at all; an operational definition describes that behavior precisely enough to measure. |
Test yourself
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Question 1The operational definition says crying is timed from the first cry until crying stops, and that a pause of less than 5 seconds does not end the episode. Crying begins at 10:00:30, pauses at 10:02:00, starts again at 10:02:03, and stops for good at 10:04:00. How should the RBT record this?
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B: One episode lasting 3 minutes 30 seconds. Because the pause lasted only 3 seconds, the definition makes this a single episode. It is timed from onset (10:00:30) to offset (10:04:00): 3 minutes 30 seconds. Onset and offset rules in the definition decide how episodes are counted and timed.
- A: The 3-second pause is shorter than 5 seconds, so by the definition it does not end the episode.
- C: The episode did not end at 10:02:00, because the crying resumed within 5 seconds.
- D: By the definition the pause is part of the episode, so the episode is timed from first onset to final offset without subtracting it.
Task A.1 · 40-hour curriculum section C
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Question 2A plan calls for frequency recording of swearing during a 2-hour community outing. Halfway through, the swearing becomes so frequent that the RBT cannot keep an accurate count. What should the RBT do?
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A: Note the problem and tell the supervisor promptly. The RBT implements the measurement system the supervisor designed. When it cannot be carried out accurately, the RBT documents what happened and reports it so the supervisor can decide whether to change the procedure.
- B: Changing the measurement procedure is a decision for the supervisor, not the RBT.
- C: An estimate made afterward is not data from observation.
- D: Changing what counts as an occurrence alters the operational definition without the supervisor's approval.
Task A.1 · 40-hour curriculum section C · RBT Ethics Code 2.02
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Question 3The plan says to count aggression, defined as hitting, kicking or biting. A client pushes a peer, and the RBT is unsure whether to count it. What should the RBT do?
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C: Follow the definition and ask the supervisor. The operational definition decides what counts as an occurrence. Pushing is not listed, so the RBT records according to the definition and asks the supervisor to clarify; the supervisor decides whether to revise it.
- A: Counting behavior that is not in the definition makes the data inconsistent with other sessions and observers.
- B: Stopping data collection leaves the rest of the session unmeasured.
- D: Only the supervisor can change an operational definition.
Task A.1 · 40-hour curriculum section C · RBT Ethics Code 2.06
Answer every question to see your score.
On the RBT exam
This term belongs to task A.5 Describing behavior in observable, measurable terms in content area A, Data Collection and Graphing, which is 13 of the 75 scored questions.