Crew performance measurement via activity sampling

Three methods of measuring the performance of construction crews are described and compared. These are: (1) Work sampling; (2) group timing technique; and (3) five-minute rating. By gathering data from a time-lapse film, the three methods can be compared for the same operation. Work sampling is shown to provide important information about the characteristics of delays. Considerable time is lost because of waiting for materials and for instructions. The group timing technique provides production data that is very different from work sampling. It is suggested that this technique can be used to validate estimating data regarding cycle times. It is also shown how a crew balance index can be determined which will allow the manager to evaluate if the crew size is appropriate for the way the work is being performed. The five-minute rating is shown to be a quick estimator of the delay time of a crew. It is shown that the reliability of the five-minute rating is not as good as that of work sampling of group timing technique. Various parameters are calculated throughout, and it is suggested that over a period of time, these can be used to monitor crew performance.