A comparison of buffer sizing techniques in the critical chain method. case study

Abstract

The presented paper is an attempt to evaluate the application of different buffer sizing methods (within the critical chain approach) to a real-life project, in order to show that it is important to choose consciously one of the existing methods. The implementation of the different approaches to the buffer sizing procedure resulted in eight unique schedules. Once all the methods were implemented, the authors of this paper stumbled upon 2 inconveniences (slack vs. buffer, splitting up buffers). Funding solution for these handicaps caused obtaining eight more schedules. In order to evaluate all the determined solutions, the authors decided to establish a simulation study. A random dataset was generated of 2000 observations using the mean and variance calculated for the probability distribution determined by three possible durations (optimistic, expected and pessimistic) given by the project team members. To validate the performance of different methods, two penalty systems were designed. The test results indicate which specific buffer sizing technique performs best in the presented case, taking into account the attitude of the decision maker. The simulation study is the proposal of a method to be applied in each case of the critical chain method application, because it makes the use of the critical chain method more effective