Whole Interval Recording

Whole interval recording is one type of 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 10 minute observational session may be separated into 1 minute intervals with ten boxes that are used to record the occurrence of behavior. In whole interval recording, the observer marks down whether a behavior occurs throughout the entire interval by placing an "X" for occurrence and a "O" for no nonoccurrence.

Whole interval recording means that the observer is interested in behavior that occurs during the entire interval. Examples of ongoing behaviors that can be observed using whole interval recording include writing, walking, reading, or working on a given assignment.

Once the recording is complete, the observer counts the number of intervals in which behavior was observed and a percentage of intervals with the behavior is documented. For instance, a teacher may be interested in whether a student is on-task which has been defined as looking at the teacher while he is talking, talking to the teacher, or looking at the assignment. If these behaviors occurred throughout six of the ten intervals, then the student engaged in the behavior of interest during 60% of the observational session.

A stopwatch or wrist watch is often used to keep track of intervals with a clipboard holding a recording sheet. A tape recording with a sound indicating the end of an interval can also be used to alert the observer and help him or her keep track without having to spend time looking at a timing instrument.

The advantage of the whole interval recording method is that it provides an estimate of the duration of a behavior and provides information about where behaviors are occurring or not occurring within an observational session. A major disadvantage of whole interval recording is that is requires an observer's undivided attention. Teachers interested in this measurement strategy may need to ask someone else to observe and collect whole interval data for them while they are working with students or engaged in instruction. Observing and recording data can be challenging, especially if using a stopwatch since the person recording must attend to both the timing of intervals as well as the student.

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 count.

If you are interested in measuring ongoing behaviors that you know will continue across intervals, use the whole interval recording method.