Proactive productivity management at job sites: Understanding characteristics of assumptions made for construction processes during planning based on case studies and interviews

During planning and execution of construction projects, project planners and managers make various assumptions with respect to execution of construction activities, availability of resources, suitability of construction methods, and status of preceding activities. However, not all of these assumptions are explicitly documented and verified before the construction activities start. Decisions made based on invalid assumptions can negatively impact the outcomes of construction projects, such as rework, activity delays, and extra material cost. To address the problems caused by invalid assumptions, this paper proposed to develop a formal approach to capture and represent assumptions and proactively verify assumptions to reduce the uncertainties associated with construction projects. To develop such a formal approach, an initial step is to identify characteristics of assumptions. The research team conducted two detailed case studies (i.e., a bridge rehabilitation project and a research lab renovation project) and seven interviews with construction professionals who have experience between 12 and 50 years. This paper provides a detailed discussion on the assumptions identified from case studies and interviews. The developed categorization of assumptions and the general characteristics of assumptions can serve as the foundation for a formal representation of assumptions, which helps construction professionals to proactively verify assumptions so as to avoid negative impacts of invalid assumptions on construction planning and execution.