Velocity

Velocity is an average amount of work (measured in story points) that the scrum team completes each sprint.

Knowing the velocity of a team enables the product owner to plan the delivery of future releases. The velocity of a new scrum team may be volatile, as they get accustomed to working in a new structure. Over time, the team’s velocity should increase, until the team is established. Once established, the team’s velocity should be fairly stable. The amount of work that they can complete should be predictable. Decreases in velocity should be evaluated to determine whether process changes are needed to reestablish team performance.

Although velocity is a measure of a team’s performance, you can not compare the velocity of two different scrum teams. Two different teams might assign different story points to the same story. The value that that a team to assign to a story is simply a value that is relative to some reference story. If one team is able to complete 40 story points in a sprint and another team of the same size can only complete 30 story points within a sprint of the same length, that does not necessarily mean that the team that completes 40 story points is doing more work than the team completing 30 story points. It could mean that one team is using higher values for each of their user stories.

When using velocity as a measure of performance, make sure that you are comparing a team’s velocity from one sprint to the next rather than comparing one team’s velocity to another’s.