Criticality measurement in fuzzy project scheduling

Abstract

Critical path method provides complete time analysis of project activities and identifies the critical ones based on deterministic time and cost estimates. In real-life, duration estimate of project activities contains some sort of uncertainty. Program evaluation and review technique (PERT) has been used early for dealing with uncertainty. Monte Carlo simulation (MCS) is used to overcome some pitfalls of PERT; however, MCS is time-consuming and requires large amount of data. Accordingly, fuzzy-set theory is used to quantify uncertainty associated with activities’ durations. Several fuzzy-based techniques have been proposed; however, some difficulties are encountered in determining late times of activities and degree of criticality. The aim of this article is to present an analytical method for measuring criticality in a project network with fuzzy activity durations. A proposed method for measuring criticality degree (CD) of both project paths and activities is presented, avoiding pitfalls of previous fuzzy methods. Linear fuzzy activities’ duration – that is commonly used in construction – is assumed. An example application is worked-out to illustrate the steps of the proposed method. The results show that the proposed method is precise and effective for determining CD of both project paths and activities.