Interval recording answers: in what share of an observation did the behavior show up? The observation is split into equal intervals, each one is marked + or −, and the score is the percent of intervals marked +.
12 templates in the library use interval recording (% of intervals), across 3 skills. Each prints the interval recording sheet.
When to use it
Engagement and on-task behavior during long work periods or lessons
Behaviors too frequent or too long to count one by one, such as humming or out-of-seat
Observing several students in turn: momentary time sampling lets one adult check each student at the cue
Not for skills with right and wrong answers: those need accuracy or opportunities
How to record it
Write the behavior's definition and pick the method: partial interval, whole interval, or momentary time sampling.
Choose the interval length and the number of intervals, such as 10 intervals of 2 minutes in a 20-minute block.
Start a vibrating timer (or the interval timer in the IEP Atlas workspace) so every interval has the same length.
Mark each interval: partial (+ if it happened at any point), whole (+ only if it lasted the whole interval), momentary (+ if it is happening when the interval ends).
Leave unobserved intervals blank, then divide + marks by intervals scored and record the percent with the date.
Writing the criterion and mastery rule
Name the observation in the condition: "during a 20-minute independent work period".
Write the criterion as "in at least N% of 2-minute intervals" (or "in no more than N%" for a behavior to reduce).
Name the method in the measurement phrase: "as measured by momentary time sampling".
Pair it with a mastery rule that counts observations, such as "on 4 of 5 observed days".
Common mistakes
Changing the interval length between sessions, so the percents no longer compare.
Checking only when the student stands out, instead of at the fixed cue.
Counting an unobserved interval as a −, which lowers the percent unfairly.
Using partial-interval recording for a behavior to grow; it overestimates and can show progress that isn't there.
Goal examples measured this way
Numbers are illustrative. Set targets from the student's own baseline data.
Classroom Expectations & Routines
Use the posted voice level during each part of the lesson
By the annual IEP review date, during a 20-minute work period with the voice level posted and checked by the observer every 2 minutes, the student will use a voice at or below the posted level at each check independently in at least 90% of 2-minute intervals, across 3 consecutive weekly data summaries, as measured by momentary time sampling collected 3 times per week, 10 checks per period, summarized weekly.
By the annual IEP review date, during a 20-minute independent seatwork period scored at 10 momentary time-sampling checks, the student will be engaged with the assigned task by writing, reading, solving, or handling the task materials independently in at least 80% of 2-minute intervals, on 4 of 5 observed days, as measured by momentary time sampling collected three times per week.
By the annual IEP review date, during a community-based instruction outing in a store or public building, the student will stay within the agreed distance of the group and stop when the group stops independently in 100% of 10-minute intervals, across 3 consecutive outings, as measured by whole-interval recording collected at each outing, recorded in 10-minute intervals.
What is the difference between partial-interval, whole-interval and momentary time sampling?
Partial-interval marks + if the behavior happened at any point in the interval. Whole-interval marks + only if it lasted the whole interval. Momentary time sampling marks + only if the behavior is happening at the instant the interval ends.
How many intervals do I need?
Ten or more intervals per observation gives a usable percent; with fewer, one interval swings the score a lot. Judge progress across several observations rather than one.
Can I take interval data while I teach?
Yes, with momentary time sampling and intervals of a minute or more. A vibrating timer (or the interval timer in the IEP Atlas workspace) gives the cue, you glance, and tap + or −.
IEP Atlas Pro
Turn these goals into progress reports
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Count trials, prompts, and minutes live in the session; the graph and trend line draw themselves; progress reports are drafted from your data.