Some empirical justification for a modest proposal regarding data acquisition via intermittent direct observation

Computer simulations of behavior and event records of a child's visual fixation on an adult person were generated and sampled using a modified time sampling procedure. The modified approach required making two independent scoring judgments per observation interval: if the behavior was initiated within the interval, the interval was scored; if the behavior was ongoing precisely at the end of the interval, the interval was again scored. The results showed that the within-interval and end-of-interval scores yielded, respectively, estimates of behavioral frequency and duration. The accuracy of the estimates was a function of the number of observations. Several field studies demonstrated high agreement among observers who employed the measurement system.