Quantification of Project Execution Complexity and its Effect on Performance of Infrastructure Development Projects

Abstract

Growing complexity is one of the main reasons behind the failure of many projects. Thus, identifying and measuring complexity is crucial to the success of any project. Various schedule complexity indices have been proposed in the past, but a comprehensive complexity measurement tool encompassing factors of schedule along with other important project constraints, such as time and scope, is still missing. First, a theoretical framework consisting of 46 complexity factors has been developed through literature review followed by its refinement through a three-round Delphi study. The complexity factors are categorized into three categories, namely, Schedule complexity, Scope complexity and Cost/Resource complexity. The Project Execution Complexity Index (PECI) tool is proposed, followed by development of a questionnaire in order to compute PECI values and validated using three infrastructure development projects during the planning phase. Finally, in the execution phase, the performance of the projects is measured through earned value analysis. PECI values are then mapped with project performance indices (i.e., schedule/cost performance index) in order to assess the effect of project complexity on the performance of projects. The results showed that projects with higher complexity tend to have larger cost or schedule overruns. These case projects are also ranked according to the degree of their complexity on the complexity scale. This ranking can help decision makers to decide which projects should be included in the portfolio and which projects need prioritizing through assigning resources more efficiently. The proposed PECI tool may also help project managers to better anticipate prospective difficulties during the initial stages of the project lifecycle.