All frequent flyers know the drill if you're like me and have a reserved seat in the exit row. The flight attendent gives the personal talk about our willingness to be in the exit row, how to open the door, than reminds us that the door weighs approximately 32 lbs - just like it says on the Placard.
Now what does appoximatey actually mean? Approximatley 32 lbs could be the door weighs between 31 and 33 pounds. Our it could weigh between 25 and 50 pounds.
No Simple Point Estimate Can Be Credible Without The Variance
This is the phrase that must be used at all times will doing project work. When someone states the cost of the project, you ask what is the variance? When they state the planned duration you ask what is the confidence level for that estimate.
If they answer what do you mean you know immdediatly that project will be late and over budget. They have no clue of what it will cost or when they will be done.
Back to the Agile paradigm one more time. Agile is essentially a time boxed approach to cost and schedule. The features are the variable. This is a wonderful concept for customer that can accept functions that vary. But what about those customers that need all the features, for some level of confidence of cost and schedule.
We now need a process that can produce a baseline plan that produces ALL the needed capabilties, on or before the planned completion data, at or below the planned cost. This will be a risk adjusted cost and schedule.