Spot Observation Sampling

Spot observation sampling is a time-allocation technique in which an observer arrives at randomly chosen moments and records, instantaneously, exactly what each visible person is doing at that instant — not what they were doing before or after. Because the moments are sampled at random across the daily and seasonal round, the proportion of spot observations that fall in a given activity is an unbiased estimate of the proportion of time people spend in that activity. It turns a scatter of brief snapshots into a quantitative budget of how a community allocates its waking hours.