Managing the Cone of Uncertainty

Some of you may not be familiar with the term "Cone of Uncertainty". In the Project Management and Requirement Management world it is often called "Scope". So what is the Cone of Uncertainty? If you have ever watched a weather report as they monitor the progress of a hurricane you will notice that the further the hurricane is from shore the larger the potential impact. As the hurricane nears, the potential impact becomes smaller and smaller as predictability improves.

It is no different in system development. Consider the early phases of a project, when we are far from understanding the potential impact of the system. Our estimates are based on what we used to call WAGs (Wild A** Guesses). Somehow these become finalized in a project schedule. I feel I must state here that we never came close to meeting that schedule. As we began to work through the requirements, our understanding of the system increased and our estimates began to change, and get closer to the truth during each phase of development.

So what can we do to manage this uncertainty? There is no silver bullet, of course. But there are some things we can do to mitigate this risk.

• Many environments change so slowly that they can be considered static. Know your environment and how quickly and often it changes.

• Before making any significant investments, uncertainty should be reduced to a comfortable level. Snap decisions are never a good thing. If there is uncertainty in new technology or new approaches, mitigate the risk with the input of experts.

• Systems engineering is volatile; external pressures increase uncertainty over time. External pressures can affect the entire development process. When those external pressures arise, assess and determine the importance of those pressures and identify their impact to the current development plans.

• You must actively and continuously work to reduce the uncertainty level. Just ignoring uncertainty will not make things any better. Identify uncertainty and meet it head on.

• The Cone of Uncertainty is narrowed both by research and by decisions that reduce variability. This is a key part of the System Engineering tasks. Document decisions and rationale and the resulting requirements so you can move on.

• These decisions are about scope, what is included - and what is not included. Continually assess what is in and what is out. Remember that today the capability might be in, and tomorrow it may be out (as Heidi Klum says on Project Runway). In an Agile environment this assessment is made almost daily.

Many process improvement efforts today are targeted towards reducing the size of the cone of uncertainty.

• Quality requirements from solid elicitation techniques

• Improved estimation techniques

• Formal requirements management

• Formal change management

• Proper and complete testing

Remember, that if these decisions change later in the project then the cone will widen. As always, requirements play a key role in managing the Cone of Uncertainty.

By: Marcia Stinson