Combining Risk Factors

In “Waltzing with Bears” Tom DeMarco and Tim Lister introduce the very useful concept of the “Uncertainty Diagram”, the probability distribution for project metrics such as delivery date, expenditure or benefit delivery. This is used, for example, to assess the likelihood of delay from a given risk.

However, they rely entirely on Monte-Carlo simulation. I believe that where the curve is defined by, or can be approximated by, a few discrete points, a relatively simple analytical solution can then be used in place of simulation.