Critical path method (CPM) is categorized as a popular tool for scheduling mega projects. In this paper, to enjoy the advantages of interval type-2 fuzzy sets (IT2FSs) and better address uncertainty for the activities’ attributes, a new analysis model is presented to determine the critical path under an IT2F-environment. Also, new efficient factors on specifying critical paths, such as time, cost, risk, safety, and quality (TCRSQ), are presented to achieve a more robust plan assisting in megaproject success. Moreover, an IT2F weighting approach is suggested for specifying the weights of TCRSQ factors. Furthermore, a new IT2F-approach employing the relative preference relation is expressed for identifying the importance of each expert. Consequently, a new model for critical path determination procedure by considering efficient factors is developed under the IT2FSs environment. Finally, to demonstrate the suggested model's capability and the calculation process, an application from the previous research is solved. Manuscript profile