Which approach involves the observer noting the presence or absence of behavior?

The approach where the observer notes the presence or absence of behavior is interval recording. This method involves dividing the observation period into intervals and recording whether the behavior occurred during each specific interval. This technique allows for a systematic way to collect data on behaviors, making it easier to analyze trends over time.

In interval recording, an observer may use either whole-interval or partial-interval methods, determining whether to record the behavior only if it happened throughout the entire interval, or if it occurred at any point during the interval. This approach is particularly beneficial for understanding the frequency and duration of behaviors within set time frames, making it effective for tracking various behavioral patterns in individuals with mild to moderate disabilities.

The other methods mentioned serve different purposes: duration recording focuses specifically on how long a behavior lasts, error analysis examines the types and frequency of mistakes made by a learner, and event recording is concerned with counting the number of times a specific behavior occurs, rather than simply noting its presence or absence across intervals.