An interpretive structural modelling approach to determine the critical causes and effects of design changes in public infrastructure projects.

A successful completion of infrastructure projects in developing countries is greatly affected by poor and incomplete design. In this regard, it is imperative to study the major causes and overall impacts of design change in infrastructure projects across the public market. The primary objective of this research is to identify and analyze the major causes that lead to design change in the implementation phase of construction projects. In addition, the study aims to examine the impacts of design change in terms of cost overrun and time variance during the design and construction stages of infrastructure construction projects. To achieve these goals 48 critical causes and 7 impacts of design changes were identified through a systematic literature review, 23 key causes and 7 impacts were then refined according to the opinions of relevant experts involved in infrastructure projects. Then, a structured questionnaire survey was employed to collect data from various sources. More so, 31 projects were identified as part of the case studies conducted to evaluate the impacts of design change of infrastructure projects. The study analyzed the collected data by Interpretive Structural Modeling (ISM) and to classify the causes using the Matrice d'Impacts Croisés Multiplication Appliquée à UN Classement (MICMAC) technique. The result showed that Inadequate project objectives, Unrealistic clients demand, and Obstinate nature of client are the top factors. The findings are believed to be helpful for practitioners, and policy makers to trap the key factors, causes and impacts of design changes across the Ethiopian construction industry. [ABSTRACT FROM AUTHOR]