Project Completion Method: Stochastic Project Scheduling Simulation

Manuscript ID: CO/2003/022870 Specialty Area: Cost & Schedule Audience: Researchers PROBABILITY OF PROJECT COMPLETION USING STOCHASTIC PROJECT SCHEDULING SIMULATION (SPSS) Dong-Eun Lee1 ABSTRACT This paper introduces a software, Stochastic Project Scheduling Simulation (SPSS), developed to measure the probability to complete a project in a certain time specified by the user. To deliver a project by a completion date committed to in a contract, a number of activities need to be carried out. The time that an entire project takes to complete and the activities that determine total project duration are always questionable because of the randomness and stochastic nature of the activities’ durations. Predicting a project completion probability is valuable, particularly at the time of bidding. SPSS finds a longest path in a network and runs the network a number of times specified by the user and calculates the stochastic probability to complete the project in the specified time. SPSS can be used by a contractor (1) to predict the probability to deliver the project in a given time frame, and (2) to assess its capabilities to meet the contractual requirement before bidding. SPSS can also be used by a construction owner to quantify and analyze the risks involved in the schedule. The benefits of the tool to researchers are (1) to solve PERT problems; (2) to complement Monte Carlo simulation by applying the concept of project network modeling and scheduling with probabilistic and stochastic activities via a web based Java Simulation which is operateable over the Internet, and (3) to open a way to compare a project network having different distribution functions.

Keywords: Critical path method, Monte Carlo method, probability, risk analysis, scheduling, simulation, stochastic models.
1. Ph.D. Candidate, Construction Engineering and Management Program, Department of Civil and Architectural Engineering, Illinois Institute of Technology, 3201S. Dearborn St., Chicago, IL

References: Contractor (Element 3 in ISO 9001) • Ensuring capacity in initial phase • Minimizing probability of delay • Monitoring the dynamic nature of progress Construction Owner • Completion forecasting • Project financing forecasting