Record Project Estimates and How You Derived Them

Record Project Estimates and How You Derived Them (#15 in the series 21 Project Management Success Tips)
By Karl E. Wiegers

When you prepare estimates for your work, write down those estimates and document how you arrived at each of them. Understanding the assumptions and approaches used to create an estimate will make them easier to defend and adjust when necessary. It will also help you improve your estimation process. Train the team in estimation methods, rather than assuming that every software developer and project leader is instinctively skilled at predicting the future. Develop estimation procedures and checklists that people throughout your organization can use.

The Wideband Delphi Process FlowAn effective group estimation technique is the Wideband Delphi method. Wideband Delphi builds on the principle that multiple heads are better than one. The Delphi estimation method asks a small team of experts to anonymously generate individual estimates from a problem description and reach consensus on a final set of estimates through iteration. The figure below illustrates the Wideband Delphi process flow. The outputs from the process include a complete list of project and quality-related tasks and an estimate for each task, in whatever units the team chose (such as dollars, weeks, or labor-hours). Participation by multiple estimators and the use of anonymous estimates to prevent one participant from biasing another make the Delphi method more reliable than simply asking a single individual for his best guess.

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.