ABA glossary
Partial-interval recording
Definition
A discontinuous method in which an interval is scored if the behavior occurs at any point during it, even once or briefly. It tends to overestimate how much of the session the behavior took up.
In plain words
With partial-interval recording you only need to see the behavior once in an interval to score it, and you can stop watching for that interval as soon as it happens. That makes it practical for frequent, brief behaviors such as calling out, hitting, or vocal stereotypy. Because a single brief instance scores the whole interval, it overestimates duration; because several instances in one interval still score only once, it underestimates count. It is often chosen for behaviors to decrease, since the overestimate keeps progress from looking better than it is.
Example from a session
During a 10-minute circle time divided into 10-second intervals, the RBT scores any interval in which Leo calls out at least once. Leo calls out three times in one interval and once in another, so both are scored and the rest are not. The RBT reports the percentage of intervals with calling out, as the plan says, and does not try to count each call-out.
For BCBA candidates and supervisors
Partial-interval recording is the classic choice for reduction targets and for behaviors that are hard to count, but analysts know its data can mislead in both directions: a behavior that becomes briefer within intervals may look unchanged. Shorter intervals reduce the overestimate. When a decision hinges on the exact amount of behavior, analysts compare the partial-interval data with a continuous measure in some sessions.
Often confused with whole-interval recording, momentary time sampling
Partial interval scores the interval if the behavior occurs at any time during it. Whole interval scores it only if the behavior lasts the entire interval. Momentary time sampling scores it only if the behavior is happening at the instant the interval ends. Partial interval overestimates, whole interval underestimates, and MTS can go either way.
Exam tip
"At any time during the interval" or "at least once" means partial interval. If the question asks which method overestimates or suits a behavior to decrease, choose partial interval.
Can you spot partial-interval recording in a scenario?
Practice RBT A.2 with exam-style questions and instant feedback.