Research On The Project Schedule Management Based On The Critical Chain

The project schedule management plays a key role in the success of a project. However, due to the general project schedule management approaches' rigidness, sidedness and inefficiency, they are increasingly difficult to meat the progress of modern project management requirements. Therefore, the research on the critical chain technology which may compensate for the defects in the general project schedule management has important theoretical and practical significance.The paper adopts the literature analysis, the comparative analysis, the empirical analysis and the combination of qualitative and quantitative methods. Firstly, the paper combs the related theories of the project schedule management, including the project schedule plan theory, the project schedule control theory, the theory of constraints and the critical chain theory. Secondly, the paper analyzes the problems and the reasons of the general project management approaches in the application; and describes the improvements of the critical chain technology in the time estimation of the project activities, the project schedule planning steps and the project schedule control. Thirdly, the paper builds a project schedule management model based on the critical chain technology from three aspects, including identifying the critical chains, setting the buffer size, and setting the buffer management mechanism. Lastly, the paper uses the model built in the paper in an example, conducts a Monte Carlo simulation, and compares its results with the outcomes based on CPM/PERT methods.The paper comes to the following conclusions: The critical chain technology compresses the safety time, and sets the buffers to aggregate the safety time. So it effectively eliminates the affects of the man-made factors, such as Parkinson's Law, Murphy's Law and Students' Syndrome and effectively compensates for the deficiencies of the general project schedule management approaches. The model built in the paper bases on the three-point time estimates of the CPM/PERT method, adopts the most optimistic time for the time estimation of the activities in the project management model based on the critical chain. Therefore, it not only eliminates some safety time, but also avoids the arbitrariness by using the 1/2 of the program duration as the time estimate. The model built in the paper introduces the uncertainty factorλ, the position weight coefficientα, and the risk elasticity coefficientβ. So, it offsets the common buffer without considering the difference of the project activities' uncertainty, and enhances the reasonableness of the buffer size setting. The model built in the paper re-defines the ratio of the buffer consumption and the completed project schedule, and then decides to take measures or not. So, it makes up the common buffer management mechanism' that the consumption of buffer is uniform and reflects the acceleration characteristics of the consumption of buffer.