ABSTRACT
One of the restrictive assumptions made in the previous chapters was that estimated activity time was deterministic and accurate. Obviously, this assumption is not valid in a real-world project, yet relaxing the assumption introduces a nondeterministic answer regarding when the project will be finished. This means that management and user stakeholders are going to have to deal with a different kind of completion discussion. The proper answer will no longer be to say that the project will be finished on June 1. Instead, the answer will be couched in statistical terms such as “we have a 50% chance of finishing by June 1 and a 90% chance of completing by August 15.” It is this characteristic that keeps variable time schedules from being popular. Stakeholders seem to want a single answer even if it is wrong (which it will be most of the time). Figure 22.1 shows what this result might look like with a histogram of probabilistic completion dates. This chapter will explore a classical technique to accomplish this type of analysis.
