Interval recording
Last updated
Interval recording divides an observation into short, equal intervals and records whether a behavior occurred during each one.
Topic: Measurement and data collection
In plain terms
In partial-interval recording, the observer marks an interval if the behavior happened at any point in it; this tends to overestimate behavior and suits behaviors you want to decrease. In whole-interval recording, the behavior must last the entire interval; this tends to underestimate behavior and suits behaviors you want to increase, such as staying engaged. Results are reported as the percent of intervals marked.
How it shows up in an IEP
Interval methods are useful when behaviors are too frequent or too long to count individually. They need a timer or vibrating cue, and they demand the observer's attention, so a teacher running a lesson may prefer momentary time sampling.
Example
A school psychologist observes for 10 minutes in 15-second intervals and marks off-task behavior in 22 of 40 partial intervals, or 55%.
Related terms
- Momentary time samplingMomentary time sampling records whether a behavior is happening at the exact moment each interval ends, rather than watching continuously.
- Duration recordingDuration recording measures how long a behavior lasts, from the moment it starts to the moment it ends.
- Event recording (frequency)Event recording is a way of collecting data by counting each time a behavior or skill happens during a set observation period.
- Operational definitionAn operational definition describes a behavior in observable, measurable terms, so different people would agree on whether it happened.
On IEP Atlas
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