## Chapter 16. Estimating Velocity

*“It is better to be roughly right than precisely wrong.”*

—John Maynard Keynes

One of the challenges of planning a release is estimating the velocity of the team. You have the following three options:

• Use historical values.

• Run an iteration.

• Make a forecast.

There are occasions when each of these approaches is appropriate. However, regardless of which approach you are using, if you need to estimate velocity you should consider expressing the estimate as a range. Suppose you estimate that velocity for a given team on a given project will be 20 ideal days per iteration. You have a very limited chance of being correct. Velocity may be 21, or 19, or maybe even 20.0001. So instead of saying velocity will be 20, ...