Operational Definitions in ABA

In ABA, an operational definition describes a target behavior in a way that is:
- Observable
- Measurable
- Easily understood by others
Accurate data taking requires the data taker to identify exactly what the target behavior is and is not.
- Otherwise, they may under or over report behavior data.
Commonly used words and phrases to describe behaviors are often too vague or opinion-based.
- They don't specify important information needed to take data.
- They do not provide information on contexts wherein the behaviors might be expected or non-problematic.
- Therefore, instances might not need to be reported.

"Throwing a fit" is not an operational definition because it can be interpreted differently by different people.
- To one person, throwing a fit may be screaming for a few seconds.
- For another, it may be prolonged screaming.
- For a third, it may be hitting people while making an angry face.
- Data taken by these three people would look wildly different.

Instead of using "screaming", use:
- Any instance in which James engages in a vocalization louder than is typically used for communication for longer than five seconds, during which time he may or may not produce tears.
- With this definition, it is much easier to know when to take data.

Using "throwing things alone" as a definition fails to take into account whether or not data should be recorded on the behavior in contexts wherein throwing is acceptable, such as while playing baseball in PE class.
- One technician on the team may take data including throwing baseball in PE, and one may not, leading to data that does not accurately illustrate the prevalence of the target behavior.
Instead of using "throwing", use:
- Any instance in which James moves objects not intended to be thrown through space farther than one foot using one or both hands or arms.