In spite of the development of theories related to the early stages of the project life cycle (feasibility studies and initial planning), it is still unclear to what extent the project stakeholders have sufficient belief regarding the necessity and implementation of these initiation phases in practice. This research has been conducted with the aim of measuring the efficiency of implementation of feasibility study in construction projects (especially in Iran) and proposing a solution to improve its efficiency in the future. The data collection tool is questionnaire based and has been measured and analyzed using the relative importance index (RII) of the following items: Measuring the efficiency of existing feasibility methods, Developing and controlling its performance and Knowledge-based feasibility study. The results of this analysis revealed the factors such as (Sequence of tasks, bottom-up management and appropriate work breakdown structure) that are of particular importance for the development of the initial phase of projects. Also, the general findings indicate that this research can be used to clarify how to strengthen the link between related theories and the use of these theories in the implementation of projects in practice. In addition, this research can provide new insights for project managers and stakeholders towards the new knowledge-based management strategies and tools and also can implement the project team training system to improve the level of insight and understanding of project stakeholders from the early stages of the life cycle in the current practices of construction projects.