The cost of construction projects right from the inception to completion stage is becoming a matter of great concern, recently, especially among clients and beneficiaries, because of the rising interest rates, scope change, among other factors responsible for cost overruns. Hence the need to understand the complexities of cost overrun in the construction sector has become more important. This study therefore aims to identify the major complexity attributes of cost overruns in construction projects to suggest practical solutions in addressing them. Literature study along with semi- structured interview is used to identify the complexities of cost overrun and on the basis of the self-assessment tool maturity level of the complexity attributes, the major attributes behind cost overrun are identified based on the results of the analysis and further suggestive measures are given.

Keywords : Complexity, Cost Overrun, Self-Assessment Tool.