Whole interval recording
Whole interval recording scores an interval only if the target behavior occurs throughout the entire interval, without stopping.
The session is divided into equal, usually short, intervals. The observer watches continuously during each interval and scores it only if the behavior was present from the first second to the last. If the behavior stops even briefly, the interval is not scored. Results are reported as the percentage of intervals scored.
Whole interval recording tends to underestimate the total amount of behavior, because any interval with a brief break is counted as zero even if the behavior filled most of it. For that reason it is commonly used for behaviors the team wants to increase and that should continue over time, such as on-task behavior, cooperative play or staying seated. The conservative estimate means improvement is less likely to be exaggerated.
It suits behaviors that last a while. It is a poor fit for brief behaviors like hitting, which will almost never fill a whole interval. It also demands constant attention, so it can be hard for an RBT who is teaching at the same time. Shorter intervals make the data more accurate but harder to collect.
Example and non-example
| Example | An RBT watches a student during independent work in 20-second intervals and scores an interval only when the student worked on the worksheet for all 20 seconds. |
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| Non-example | Scoring an interval because the student worked for 12 of the 20 seconds is partial interval recording, not whole interval recording. |
Don't confuse it with
| Partial interval recording | Whole interval needs the behavior for the entire interval and underestimates; partial interval needs only one occurrence and overestimates. |
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| Momentary time sampling | Whole interval requires watching the full interval; momentary time sampling checks only the moment the interval ends. |
Test yourself
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Question 1A classroom RBT uses 20-second intervals and marks an interval only if the student kept working on the assignment for the whole 20 seconds. Which procedure is this?
Show answer
D: Whole interval recording. Scoring an interval only when the behavior occurs throughout the entire interval is whole interval recording.
- A: Partial interval recording would score the interval if the student worked at any point during it.
- B: Momentary time sampling would check only at the end of each interval.
- C: Latency recording would time how long the student took to begin after an instruction.
Task A.2 · 40-hour curriculum section C
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Question 2An RBT is using 30-second whole interval recording for on-task behavior. In one interval the client works for the first 25 seconds and then looks out the window for 5 seconds. How is the interval scored?
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B: Not scored, because the client was not on task for the entire interval. Whole interval recording scores an interval only if the behavior continues for the entire interval. Any break, even a short one, means the interval is not scored.
- A: Whole interval recording has no "most of the interval" rule; the behavior must last the entire interval.
- C: Scoring an interval because the behavior occurred at some point is the rule for partial interval recording.
- D: Being on task at the start of the interval is not enough; the behavior must continue to the end.
Task A.2 · 40-hour curriculum section C
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Question 3During a 60-second interval, a client hums for 5 seconds in the middle of the interval and is quiet at all other times. How would each procedure score this interval for humming?
Show answer
C: Partial interval would score it; whole interval and momentary time sampling would not. Partial interval recording scores any occurrence in the interval, so it scores this one. Whole interval recording needs the behavior for the entire interval, and momentary time sampling needs it at the moment the interval ends; neither condition was met.
- A: Whole interval recording needs humming throughout all 60 seconds, and partial interval recording would score any occurrence.
- B: The client was quiet at the end of the interval, so momentary time sampling would not score it.
- D: Momentary time sampling looks only at the end of the interval, when the client was quiet.
Task A.2 · 40-hour curriculum section C
Answer every question to see your score.
On the RBT exam
This term belongs to task A.2 Discontinuous measurement in content area A, Data Collection and Graphing, which is 13 of the 75 scored questions.