Buffer Sized Technique in Critical Chain Management: A Fuzzy Approach

The direct application of the theory of constraints (TOC) to project management, known as critical chain scheduling, has recently emerged as one of the most popular approaches to project management. However, Goldratt´s recommendation which cut all durations estimates in half seems very arbitrary. Recently, some approaches have been introduced to overcome this problem in this field, many of them adopt probability distribution as tasks completion time and integrate the risk of tasks in order to determine the parameters of distribution. The variability and uncertainty of the duration distribution make the evaluation full of fuzzy situations. In this paper, we introduce a fuzzy method for determining project buffer sizes in critical chain project scheduling. The comparison is done by means of a simulation study using the former data set. The proposed evaluation method is simple, practical and can be easily computerized.