Discontinuous measurement involves dividing an observation into intervals and recording whether a behavior occurred during some or all of each interval (i.e., interval recording) or at the exact time of observation (i.e., momentary time sampling; MTS). Collecting discontinuous data is often easier for observers than collecting continuous data, but it also produces more measurement error. Smaller intervals (e.g., 5 s, 10 s, 15 s) tend to produce less error but may not be used in everyday practice. This study examined the most common intervals used by a large sample of data collectors and evaluated the effect of these intervals on measurement error. The most commonly used intervals fell between 2 and 5 min. We then analyzed over 800 sessions to evaluate the correspondence between continuous and discontinuous data at each commonly used interval. Intervals of 3 min or less produced the greatest correspondence, and MTS outperformed interval recording.
Keywords: Data collection; Discontinuous measurement; Momentary time sample; Observation interval; Partial interval.
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