This paper presents a risk analysis approach applied to cost-and-schedule estimates for construction projects using Intelligent Decision System (IDS) technology. The paper discusses a pilot cost-and-schedule IDS based on influence diagram technology that contains (1) a deterministic model that links and computes specific schedule and cost factors and (2) a risk breakdown structure that describes the parameters influencing these factors. The paper also describes how a user may validate the deterministic and risk models. It concludes by discussing how the IDS calculates the results using a probabilistic engine and how the results are presented to the user.