Cost overrun is a worldwide phenomenon, with inherent variability and uncertainty that influence project performance. These variability and uncertainty deserve a thorough understanding to mitigate critical overruns. Currently, several publications summarize the cost overruns of a set of projects through point estimates and not through interval estimations. This current practice of reporting statistical summaries provides incomplete information that may constrain a proper understanding of cost overruns. Therefore, this study aimed to identify the features of current reporting practices of projects' cost overruns and to discuss the benefits of using confidence intervals in such summaries. Specifically, based on a systematic review of publications, the study aimed at analyzing thirty-six papers with relevant information of project cost overruns from five world regions; comparing the summaries by reporting pattern identified; and computing the confidence intervals of aggregated cost overruns by project type. This research found that few studies on cost overrun reported range estimations, measures of variability, and data distribution information. Additionally, there were few studies with a detailed description of the research methodology. This study advocate for reports with accurate details on distribution and range estimation of cost overruns to a better understanding of this phenomenon in construction projects.