Which time sampling method tends to overestimate the amount of behavior being measured?

• A. Partial Interval
• B. PLACHECK
• C. Momentary Time Sampling
• D. Whole Interval

Answer: (A)

Time sampling methods bias the estimated amount of behavior because they rely on short observation windows rather than continuous monitoring. In partial interval recording, the observer marks the behavior as present if it occurs at any moment during the interval. Even a brief instance in that window counts, so frequent or brief bursts produce a mark in many intervals. This inflates the total amount observed across the session, making the behavior seem more prevalent than it actually is.

By contrast, whole-interval recording requires the behavior to occur for the entire interval, which tends to miss shorter occurrences and underestimate the amount of behavior. Momentary time sampling looks only at the end of each interval, so events that don’t align with that moment can be missed, yielding a different bias. PLACHECK, a group-focused variant, has its own biases as well, but it’s not the method that characteristically overestimates to the same degree as partial interval recording.

So, the method that tends to overestimate the amount of behavior being measured is partial interval recording.