Investigation on Under Estimation of Project Duration in Public Building Construction Project in Jimma Tow

Abstract

The construction industry and projects are growing rapidly in today's fast-changing world. Success in managing projects is a critical factor for the entire organization’s success. The success of a business project often depends on the accuracy of project estimates. But many projects are terminated when it becomes apparent that they significantly exceed their planned time and budget goals. Estimating project duration is not informal; as it is not an arithmetical sum of all activities. Accurate estimation of project duration and required resources become an issue of prime importance. Nowadays, project performance fails to be delivered within the original estimated schedule, and many of them are not completed. Such failures are often caused by unrealistically optimistic estimates of the time needed to complete the project activities. This paper mainly focuses on the investigation of underestimation of project duration in public building construction projects with a targeted assess the current practice of project duration estimation, to identify critical factors that affect under estimation public Building Construction Project duration, and to determine the effects of underestimation on Public Building Construction Project duration. Consequently, the survey research design was used to accomplish the objective of the study. The questionnaire was distributed to contractors, consultants, clients, and other related employees of the companies which were working under construction on building construction projects in Jimma Town. The survey questionnaire was distributed to 40 respondents who were selected purposively, representing a response rate of 85%. The data gathered through the questionnaire and interviews were analyzed by Microsoft Excel, Statistical Package for Social Science, and Relative Impotence Index. Descriptive analysis is used to summarize and interpret the data. The research result indicated the current practice of project duration estimation using expert judgment, use historical data, and using critical path methods was ranked the from1st to 3rd with RII value of 0.68, 0.66, and 0.64 respectively with factors that affect underestimation was Enhanced skills required, Technology and methodology of estimation, Technology, and methodology of construction and Incomplete and incorrect drawing with RII value0.782, 0.776, 0.753 respectively ranked from first factor up to third. Generally, from the study underestimation of project duration affects and fails to deliver all the parts of the project through time, and budget, Despite the critical role of accuracy, it shows that many aspects of the owners’ project administration and delivery process could be significantly improved when estimating project duration set out all project tasks, deliverables and set a reasonable deadline based on the complexity of work to be done.