Assessing observer accuracy in continuous recording of rate and duration: three algorithms compared.

The three algorithms most frequently selected by behavior-analytic researchers to compute interobserver agreement with continuous recording were used to assess the accuracy of data recorded from video samples on handheld computers by 12 observers. Rate and duration of responding were recorded for three samples each. Data files were compared with criterion records to determine observer accuracy. Block-by-block and exact agreement algorithms were susceptible to inflated agreement and accuracy estimates at lower rates and durations. The exact agreement method appeared to be overly stringent for recording responding at higher rates (23.5 responses per minute) and for higher relative duration (72% of session). Time-window analysis appeared to inflate accuracy assessment at relatively high but not at low response rate and duration (4.8 responses per minute and 8% of session, respectively).