Estimating Labor Productivity Frontier: A Pilot Study

摘要

Labor productivity frontier is the theoretical maximum production level per unit of time that can be achieved in the field under perfect conditions. This level of productivity is an abstraction that is useful in the estimation of optimal productivity for labor-intensive operations. This paper reports on a pilot study performed to evaluate the feasibility of a dual approach for estimating the productivity frontier for a simple electrical installation. The first approach involves the estimation of the productivity frontier by using observed durations from a time and motion study. The movements of a worker are captured by multiple synchronized video cameras. The actions that make up a particular task are identified from the video frames and categorized into contributory and non-contributory actions. The best series of contributory actions are identified based on the shortest time taken to complete a task, and a synthetic worker model is used to determine the productivity frontier as the sum of the shortest durations for each action. The second approach involves the estimation of the productivity frontier by using estimated durations on the same time and motion study. The probability distributions that best represent action durations are identified and the productivity frontier is defined as the sum of the lowest values from each of the distributions at a 95% confidence interval. The highest labor productivity value from these two strategies is taken as the best estimate of the productivity frontier. An accurate estimate of labor productivity frontier is the first step toward developing a process that will allow project managers to determine the efficiency of their labor-intensive construction operations by comparing actual vs. optimal rather than actual vs. historical productivity. Toward this end, this paper reviews relevant literature, presents the details of the proposed dual approach, introduces results from the pilot study, and evaluates the feasibility of this methodology for estimating the labor productivity frontier.