AbstractEffective communication is essential to the successful completion of construction projects, but achieving it can be difficult when there are several stakeholders. Various studies have identified and analyzed effective project-based communication indicators (EPCIs), but most have not addressed their impact. This paper strives to fill that knowledge gap by investigating the impacts of EPCIs on primary (owners, designers, and contractors) and secondary (subcontractors and suppliers) stakeholders in construction projects. To this end, a comprehensive study of the previous literature was performed to identify and classify the EPCIs. Data from 40 case studies of regional and global construction projects were collected, and a survey questionnaire was designed and disseminated to collect additional data. Cohen’s d method was employed to weight each of the EPCIs for all five stakeholders’ groups, and the findings revealed that a lack of financial resources, high turnover of craft labor, the owner’s lack of understanding of the project’s goals and objectives, a large number of approvals needed by primary stakeholders, and the number and depth of quality requirements significantly impact the quality of communication. The findings of this research will help management teams understand how project parameters impact the quality of communication among stakeholders and will enable them to develop strategies to prevent unintended consequences caused by miscommunications.