Construction projects are initiated in complex and dynamic environments res
ulting in circumstances of high uncertainty and risk, which are compounded
by demanding time constraints. This paper describes a systematic way to con
sider and quantify uncertainty in construction schedules. The system incorp
orates knowledge and experience acquired from many experts, project-specifi
c information, decision analysis techniques, and a mathematical model to es
timate the amount of risk in a construction schedule at the initiation of a
project The model provides the means for sensitivity analyses for differen
t outcomes wherein the effect of critical and significant risk factors can
be evaluated. The paper focuses on lessons learned from past projects and d
escribes a risk assessment process involving typical inputs and expected ou
tputs. The paper also briefly reviews the information technology of HyperCa
rd and Excel, which were used to develop the system.