Identification and ranking significant factors causing cost overrun in the design and construction process of buildings using the BWM method (Case study: City of Mashhad)

Introduction and purpose of the research:

 One of the main criteria to measure the success of a building project is completing it in accordance with the predicted costs.  In Iran, like many undeveloped and developing countries, the construction cost overruns are among the key issues many sections face. The city of Mashhad, as the second largest city in Iran, in the last two decades, has faced rapid urban growth and an increase in the construction, and ignoring the causes of cost overrun has led to an increase in the price of buildings. This study is aimed at identifying and ranking the factors influencing the cost overrun in construction projects in Mashhad to allow for improving the construction condition and achieve higher economic productivity.

The research has a quantitative approach and an applied objective. The components of the study, i.e., the factors influencing the cost overrun in building projects, were extracted using library studies and reviewing similar studies. Then ranked using the Relative Importance Index (RII) and the Best-Worst Technique (BWM) with the help of Excel, SPSS and Lingo software.

The findings of RII method show that according to consultants and contractors, the three factors of “poor project management, material price fluctuations and inflation” are the main causes of cost overrun in Mashhad. Owners believe that the “lack of contractor experience” factor also has a significant impact. The findings of the BWM method indicate that in addition to poor management, “poor initial planning” and “inflation” are of great importance.

The results show that the factors such as “poor project management, poor initial planning, market inflation, and mistakes during construction” are the main reasons for the cost overrun in the production procedure of building projects in Mashhad.