6 )

A particularly useful refinement uses information from Simpson's Rule, discussed in Section V.E of this chapter. First, the overall duration, or "commitment duration," is calculated as above, using the larger of each activity's nominal time or expected time. Next, a "target duration" is calculated as above using the smaller of each activity's nominal time or expected time, with corresponding target due dates for each activity. Finally, the project's schedule contingency allowance is calculated as the difference between the commitment and target durations. This contingency allowance is a valuable part of risk management, which is discussed further in Chapter 5.