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A common objective among construction managers is the improvement of construction labor productivity. One of the keys to a successful construction labor productivity improvement program is a cost-effective method of obtaining accurate and consistent labor productivity data. The rule-of-thumb has traditionally been that the accuracy and quality of labor productivity data is directly related to the resources and level of effort expended in collecting the data.
Data for productivity studies may be obtained by a variety of methods. These range from the historical site records of contractors to the actual monitoring and measurement of productivity using a variety of techniques. Each labor productivity measurement method has its application. However, a lack of consistency in productivity data collection methods has precluded the sharing of data among researchers and posed difficulties in the interpretation of the results of productivity studies. What is desirable is a simple, practical, and cost-effective productivity data collection method that yields consistent and accurate data that could be used by both researchers and construction managers for a variety of analyses.
LABOR PRODUCTIVITY DEFINITION
Construction labor productivity is essentially a single factor measure of productivity. It relates an output to only the labor workhours expended in the generation of that output. Expressed mathematically, labor productivity can be defined by the following equation:
The determination of output quantities is a relatively simple task, as they can be physically measured. The determination of the labor workhours associated with a measured output is a more contentious issue, because can be different measures of input times. These different measures of input times give rise to different labor productivity measures.
The normal workday consists of 8 hours of paid work. Due to delays, not all eight hours may be spent at work. The time that is available for work is the 8 hours less any time lost as a result of inclement weather conditions. Thus on a day when working time is lost due to adverse weather conditions, productivity measured in terms of the paid time or total hours will be less than productivity measured in terms of the time that is available for work.
On the other hand, if in addition to the time lost for inclement weather, working time is also lost due to avoidable delays,...