Cost overrun and root causes: a systematic literature review of public investment projects in Norway

Cost overrun has been frequently cited as a threatening factor of economic efficiency in public projects. Although international experiences have facilitated identification of the underlying causes, i.e., underestimation, optimism bias, etc., there is shortage of unified evidence in the context of Norway. Thus, this study puts forward to exploring the main causes of cost overrun in Norway and presenting a more unified manifest to academicians and practitioners. To achieve this goal, we have conducted a scoping review to collect and analyze the studies which investigate the factors resulting in cost overrun in the public projects of Norway. In this regard, the systematic literature review (SLR) technique is employed to minimize biased data synthesis, and ensure rigorous inferences. The derived factors are attributed to four taxonomies: technical, economic, psychological, and political, where the first group bears the highest proportion of causes. The results also indicate that external drivers, e.g., market conditions, have had the highest impact on the cost overrun which does not necessarily comply with the international inferences. Thus, further discussion is presented to highlight these distinctions which is then complemented by shedding light on the factors limiting this research.