Which of the following best describes momentary time sampling as a data collection method?

• A. Every 3 minutes, at that specific moment, Sally counts the number of students playing together vs. the number of students playing by themselves.
• B. Sally records the delay from the onset of the SD for a specific behavior and the emergence of the response she's interested in as part of a functional analysis procedure.
• C. Sally counts the total number of times a student says 'Hello, my name is Earl' in a pre-school circle time setting.
• D. At the end of a 30 minute observation period, Sally counts the percent of social engagement for all students by averaging the score on each interval.

Answer: (A)

Momentary time sampling involves taking a quick snapshot at the end of each fixed interval to decide whether the target behavior is occurring at that exact moment. In this scenario, checking every 3 minutes at that specific moment and noting whether Sally is counting students playing together versus those playing by themselves is exactly that snapshot approach. Over the observation period, the data reflect the proportion of moments in which the behavior was observed, not the total number of times it happened or how long it lasted.

The other descriptions refer to different data methods. Latency to the onset of a behavior measures how long it takes to start after a cue, which isn’t about sampling at fixed moments. Counting every instance of a behavior is a simple frequency count, not a moment-to-moment snapshot. Averaging scores across intervals at the end of a longer period sounds like interval recording, which aggregates data across intervals rather than recording the exact moment at the interval ends.

So, the described method best fits momentary time sampling.