GoalTallyQuick answer: Momentary time sampling (MTS) records whether a behavior is happening at the exact moment each interval ends, for example every 30 seconds or every minute. Mark the box if the behavior is happening at that instant and leave it blank if not. The result is the percentage of moments scored, an estimate of the share of time the behavior occurs.
Why teachers like momentary time sampling
You don't have to watch continuously. Glance up when the timer signals, mark the box, and carry on teaching. That makes MTS practical for one adult in a busy classroom and for observing several students in rotation. It works best for behaviors that last a while, such as engagement, on-task, in seat or playing with peers, rather than brief events like hitting, which are easily missed between moments.
How to use the sheet
- Choose an interval and an observation length: 30 seconds for 15 minutes gives 30 moments. Each box shows the moment to look.
- Set a signal: a vibrating timer, an interval app, or Score a session on screen, which beeps at each moment.
- Look and mark. At each signal, look at the student and mark the box only if the behavior is happening right then.
- Count and divide: marked moments ÷ moments observed × 100.
- Graph % of intervals for each observation.
Interval length and accuracy
| Interval | Moments in 15 minutes | Trade-off |
|---|---|---|
| 10 seconds | 90 | Closest estimate, but hard to keep up while teaching. |
| 30 seconds | 30 | A practical middle ground for classroom use. |
| 1 minute | 15 | Easy to do, but brief changes in behavior are easily missed. |
Shorter intervals give a closer estimate of the true share of time; longer intervals are easier but rougher. Whatever you choose, keep it the same across sessions.
Watching a group: planned activity check
A group version, often called planned activity check (PLACHECK), counts how many students are engaged at each moment and records the percentage of the group. To use this sheet that way, write “engaged / present” (for example 5/6) in each box and average the percentages.
Compare MTS with partial interval and whole interval recording before choosing a method.
Frequently asked questions
Is momentary time sampling a type of interval recording?
It's usually grouped with interval methods, but you score only the moment each interval ends, not the whole interval.
Does momentary time sampling over- or underestimate?
It can do either, depending on how the behavior is spread across the session and how long the intervals are. Shorter intervals reduce the error.
Can I observe more than one student?
Yes. Rotate between students at each moment, or make one sheet per student. Up to three behaviors can be scored in each box.
What if I'm not looking at the moment of the signal?
Score within a second or two of the signal. If you missed it, mark the moment as not observed and lower the total.
More free graphs and data sheets
Last updated · Written by the MiniTools team.