uncertainty management in time estimation of construction projects: a systematic literature review and new model development

Nowadays, the very low reliability of the project planning in certainty-based approaches, caused to use more intelligent methods for uncertainty management in construction projects. this systematic study aims to survey the methods which have been used to manage the uncertainties in time estimation of construction projects. a series of steps were undertaken during the review. the study was started with determining the purpose of the study, selecting appropriate keywords, and reducing the selected papers using some criteria. a deeper analysis was carried out on the final paper that meets the criteria for this review. the study is limited solely to papers referred in six top online databases. it aims to review how the papers have been distributed by a period of publishing and by country and the domains that these methods have been applied for. the result confirms that uncertainties which affect any project are based probability and possibility theories controlled by risk management and fuzzy logic. finally, a hybrid method for uncertainty management in project scheduling is proposed. the result of the implementation of this method in the construction project of iranian gas company shows that proposed method increases the accuracy of time estimation about 8 to 24 percent.