Defining a probability distribution function for construction simulation

Simulation is widely applied as a practical tool for planning and analysis in many industries. However, in the case of construction processes, it has not yet emerged from the research stage into practice. The lack of confiden ce in selection of a probability distribution function (PDF) for an activit y duration has limited the use of simulation as a practical tool for constr uctors. A modified beta(1)-beta(2) plane analysis by AbouRizk and Halpin re vealed that most of the construction data sets they analyzed laid in the be ta region. Based on research in experimental psychology, it is recommended that the subjective information used to define beta parameters include the minimum and maximum activity durations, as well as the mode and the 75th or 25th percentiles. This paper presents a method to determine a beta PDF for use in construction simulation modeling.