A COMPARISON OF WORK-SAMPLING AND TIME-AND-MOTION TECHNIQUES FOR STUDIES IN HEALTH-SERVICES RESEARCH

Objective. This study compares results and illustrates trade-offs betw een work-sampling and time-and-motion methodologies. Data Sources. Dat a are from time-and-motion measurements of a sample of medical residen ts in two large urban hospitals. Study Design. The study contrasts the precision of work-sampling and time-and-motion techniques using data actually collected using the time-and-motion approach. That data set w as used to generate a simulated set of work-sampling data points. Data Collection/Extraction Methods. Trained observers followed residents d uring their 24-hour day and recorded the start and end time of each ac tivity performed by the resident. The activities were coded and then g rouped into ten major categories. Work-sampling data were derived from the raw time-and-motion data for hourly, half-hourly, and quarter-hou rly observations. Principal Findings. The actual time spent on differe nt tasks as assessed by the time-and-motion analysis differed from the percent of time projected by work-sampling. The work-sampling results differed by 20 percent or more of the estimated value for eight of th e ten activities. As expected, the standard deviation decreases as wor k-sampling observations become more frequent. Conclusions. Findings in dicate that the work-sampling approach, as commonly employed, may not provide an acceptably precise approximation of the result that would b e obtained by time-and-motion observations.