We're writing two chapters in an upcoming Project Management Book, with a working title, The Gower Handbook of Project Performance for Agile, Waterfall and Everything in Between, edited by Mark Phillips. One chapter on the Principles of Risk Management and the second chapter on the Practices of Risk Management. In the book is the mention of the Cone of Uncertainty as it applies to managing in the presence of uncertanty. Since reducible and irreducible uncertainties create risk, those uncertainties need to be reduced as the project proceeds for the probability of project success to increase. Specific actions to reduce the Episuncertaintiesnaties and Margin to handle the Aleatory uncertainies are part of any good project management process.
Since there has been some confusion around the CoU in the past, about whether it can be reduced, whether there is credible data showing it is valid or not, whether those claiming it can't be reduced have any Root Cause Analysis as to why it wasn;t reduced, I thought I'd included the references we're using.
- “The Cone of Uncertainty,” Stephen Gryphon, Phillippe Kruchten, and Steve McConnell, Letters, IEEE Software, 23 (5) 2006, pp 8‒10
- “Coping with the Cone of Uncertainty: An Empirical Study of the SAIV Process Model,” Da Yang, Barry Boehm, Ye Yang, Qing Wang, and Mingshu Li, ICSP 2007, LNCS 4470, pp. 37–48, 2007
- “Reducing Estimation Uncertainty with Continuous Assessment: Tracking the 'Cone of Uncertainty’” Pongtip Aroonvatanaporn, Chatchai Sinthop and Barry Boehm, Center for Systems and Software Engineering University of Southern California, Los Angeles, CA 90089, ASE’10, September 20–24, 2010, Antwerp, Belgium, 2010.
- “Shrinking the Cone of Uncertainty with Continuous Assessment for Software Team Dynamics in Design and Development,” Pongtip Aroonvatanaporn,”Ph.D. Thesis, University of Southern California, August 2012.
- “Improving Software Development Tracking and Estimation Inside the Cone of Uncertainty,” Pongtip Aroonvatanaporn, Thanida Hongsongkiat, and Barry Boehm, Technical Report USC‒CSSE‒2012‒504, Center for Systems and Software Engineering, University of Southern California, 2012.
We have 89 other papers speaking to why, when, and how to manage projects with the CoU paradigm.
So here's the outcome
The Cone of Uncertainty is a build to goal. To make uncertanty reduce, you have to take explicit actions on the project. When you hear someone say my data shows the cone doesn't reduce, they didn't take specific actions to cause that to happen.