Integrated Project Management By Earl Hall, Juliane Johnson
Table of Contents
Chapter 8. Risk Analysis Basics Time Buffer Calculations
An imaginary experiment is created to help the project manager communicate to team members what data is needed for risk analysis. At this time, each team member is asked to provide a likelihood of task time overrunning the M estimate, which is represented in Figure 8-1 by the number where the durations begin to exceed M, subtracted from 100(100 - 80 = 20) this number is called Y; and the size of the worst case overruning W - M = D.
A project manager does not have to discuss the imaginary experiment with the project team. However, the project manager does ask each team member for three data points: M, Y, and D. He or she also leaves it up to the team members to determine when his or her task will be completed "most of the time," what the likelihood is of the task overrunning the M estimate, and what the worst case of overrun might be. These are the numbers that task leaders can be expected to estimate closely, based on past experience and discussions with other experienced people.