Planning with Risk


Most of the stories depend only on skill and teamwork. We can expect the team to perform consistently on these tasks.

But some stories depend on luck. How can you estimate how long the dice stories (for example, "Throw three ones with two dice") will take? You can compute the odds; multiply by the time it takes, on average, to throw the dice. The answer might be "On average, it will take about 30 seconds to throw three ones with two dice."

When you're planning, you need to take this uncertainty and risk into account. If the estimate is 30 seconds, it might as well take ten or 60 seconds, depending on your luck. When you have two stories that will earn you about the same business value, but one is riskier than the other, which one do you choose? Some people choose riskier stories with a higher payoff; some people prefer the stories with a lower risk. The important thing is to explicitly take the risk into account when planning.

Customers learn that it's not always possible to come up with definite estimates. Developers learn that it's hard to plan when story estimates include uncertainty.



Extreme Programming Perspectives
Extreme Programming Perspectives
ISBN: 0201770059
EAN: 2147483647
Year: 2005
Pages: 445

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net