Time Sampling: Refers to a variety of methods to record behavior at specific moments. One divides the observation period into intervals and then record either the presence or absence of a behavior within or at the end of the interval.
Partial Interval Recording: Record whether the behavior happened at any time during the interval. Tends to underestimate high-frequency behavior and overestimate duration.
When the goal is to increase behavior – use whole-interval recording because it underestimates the duration of the behavior
When the goal is to decrease behavior – use partial-interval recording because it overestimates the duration of the behavior
Whole Interval Recording: At the end of each interval, it is recorded if the behavior happened during the whole interval. The longer the interval, the more whole interval will underestimate the occurrence of the behavior.
Momentary Time Sampling: Recorder notes whether the behavior happens at the moment each interval ends. Not recommended for low frequency, short duration behaviors.
PLACHECK (planned activity check) is momentary time sampling for group engagement.
Discontinuous measurement and time sampling are the same. Momentary time sampling and partial and whole-interval recording are discontinuous methods
Time sampling are suited for behaviors that do not have a discrete start and end (for example, crying).
A measurement artifact are data that appear to exist, but only because of the way that they were measured. Discontinuous measurement procedures, especially poorly chosen aspects of it, may result in artifact.