Momentary Time Sample Recording

Momentary time sampling is called an interval recording method. An interval recording strategy involves observing whether a behavior occurs or does not occur during specified time periods. Once the length of an observation session is identified, the time is broken down into smaller intervals that are all equal in length. For instance, a 30 minute observational session may be separated into 30 intervals that are one minute in length.

In momentary time sampling, the observer looks up and records whether a behavior occurs or does not occur at the very end of the interval. A kitchen timer, alarm on a hand held watch, or a tape recording with a sound indicating the end of an interval can be used to alert the observer that it is time to look up, observe whether a behavior is occurring and to record the result on a data sheet.

A major advantage of the momentary time sample recording process is that a teacher does not need to be attending to a student's behavior all of the time. Momentary time sampling provides an estimate of behavior rather than the documentation of every occurrence and can be fairly easy to implement in class.

A major disadvantage of this measurement strategy is that it can underestimate a student's behavior since the student may engage in a behavior throughout an interval but stop right before the end of the interval. In this case, momentary time sampling would not capture a good estimate of the occurrence of a behavior.

When the behavior that you are looking at is not easily counted, you can measure the behavior by counting the number of time-intervals in which the behavior occurred. A behavior is not easily counted when:

• It is difficult to tell exactly when the behavior begins or when it ends, or
• It occurs at such a high rate that it is difficult to keep a count on it.

Since momentary time sampling can underestimate the occurrence of a behavior, it may be more useful in recording behaviors are more frequent and that last for longer periods of time.