Projects never go precisely as planned. The prudent project manager incorporates budget and schedule contingency buffers (also known as management reserve) at the end of major phases to accommodate the unforeseen. Use your project risk analysis to estimate the possible schedule impact if several of the risks materialize and build that projected risk exposure into your schedule as a contingency buffer. Even more sophisticated is the use of critical chain analysis, a technique that pools the uncertainties in estimates and risks into a rational overall contingency buffer.
Your manager or customer might view these contingency buffers as padding, rather than as the sensible acknowledgment of reality that they are. To help persuade skeptics, point to unpleasant surprises on previous projects as a rationale for your foresight. If a manager elects to discard contingency buffers, he has tacitly absorbed all the risks that fed into the buffer and assumed that all estimates are perfect, no scope growth will occur, and no unexpected events will take place. The reality on most projects is quite different. I’d rather see us deal with reality—however unattractive—than to live in Fantasy land, which leads to chronic disappointments.
Adapted from “Practical Project Initiation: A Handbook with Tools” (Microsoft Press, 2007). A condensed version of this paper was published in Software Development magazine.
Karl Wiegers, Ph.D., is Principal Consultant with Process Impact, a software process consulting and education company in Portland, Oregon. Karl’s most recent book is “Practical Project Initiation: A Handbook with Tools.” Karl is also the author of four other books and 170 articles. Karl is a frequent speaker at software conferences and professional society meetings. You can reach Karl through www.projectinitiation.com or www.processimpact.com.